Uniformize usage() and extra_usage() message ending for commands helper. (#8268)

# Description

Working on uniformizing the ending messages regarding methods usage()
and extra_usage(). This is related to the issue
https://github.com/nushell/nushell/issues/5066 after discussing it with
@jntrnr

# User-Facing Changes

None.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/strings/detect_columns.rs

@@ -33,7 +33,7 @@ impl Command for DetectColumns {
     }
 
     fn usage(&self) -> &str {
-        "Attempt to automatically split text into multiple columns"
+        "Attempt to automatically split text into multiple columns."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/encode_decode/decode_base64.rs

@@ -40,7 +40,7 @@ impl Command for DecodeBase64 {
     }
 
     fn usage(&self) -> &str {
-        "Base64 decode a value"
+        "Base64 decode a value."
     }
 
     fn extra_usage(&self) -> &str {

crates/nu-command/src/strings/encode_decode/encode_base64.rs

@@ -36,7 +36,7 @@ impl Command for EncodeBase64 {
     }
 
     fn usage(&self) -> &str {
-        "Encode a string or binary value using Base64"
+        "Encode a string or binary value using Base64."
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/strings/format/filesize.rs

@@ -43,7 +43,7 @@ impl Command for FileSize {
     }
 
     fn usage(&self) -> &str {
-        "Converts a column of filesizes to some specified format"
+        "Converts a column of filesizes to some specified format."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/split/chars.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Split a string into a list of characters"
+        "Split a string into a list of characters."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/split/column.rs

@@ -39,7 +39,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Split a string into multiple columns using a separator"
+        "Split a string into multiple columns using a separator."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/split/list.rs

@@ -29,7 +29,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Split a list into multiple lists using a separator"
+        "Split a list into multiple lists using a separator."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/split/row.rs

@@ -33,7 +33,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Split a string into multiple rows using a separator"
+        "Split a string into multiple rows using a separator."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/split/words.rs

@@ -55,7 +55,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Split a string's words into separate rows"
+        "Split a string's words into separate rows."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/camel_case.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to camelCase"
+        "Convert a string to camelCase."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/capitalize.rs

@@ -26,7 +26,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Capitalize first letter of text"
+        "Capitalize first letter of text."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/downcase.rs

@@ -26,7 +26,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Make text lowercase"
+        "Make text lowercase."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/kebab_case.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to kebab-case"
+        "Convert a string to kebab-case."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/pascal_case.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to PascalCase"
+        "Convert a string to PascalCase."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/screaming_snake_case.rs

@@ -27,7 +27,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to SCREAMING_SNAKE_CASE"
+        "Convert a string to SCREAMING_SNAKE_CASE."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/snake_case.rs

@@ -27,7 +27,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to snake_case"
+        "Convert a string to snake_case."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/str_.rs

@@ -20,7 +20,7 @@ impl Command for Str {
     }
 
     fn usage(&self) -> &str {
-        "Various commands for working with string data"
+        "Various commands for working with string data."
     }
 
     fn extra_usage(&self) -> &str {

crates/nu-command/src/strings/str_/case/title_case.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Convert a string to Title Case"
+        "Convert a string to Title Case."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/case/upcase.rs

@@ -24,7 +24,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Make text uppercase"
+        "Make text uppercase."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/collect.rs

@@ -26,7 +26,7 @@ impl Command for StrCollect {
     }
 
     fn usage(&self) -> &str {
-        "Deprecated command"
+        "Deprecated command."
     }
 
     fn run(

crates/nu-command/src/strings/str_/contains.rs

@@ -43,7 +43,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Checks if string input contains a substring"
+        "Checks if string input contains a substring."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/distance.rs

@@ -43,7 +43,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Compare two strings and return the edit distance/Levenshtein distance"
+        "Compare two strings and return the edit distance/Levenshtein distance."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/ends_with.rs

@@ -41,7 +41,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Check if an input ends with a string"
+        "Check if an input ends with a string."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/index_of.rs

@@ -65,7 +65,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Returns start index of first occurrence of string in input, or -1 if no match"
+        "Returns start index of first occurrence of string in input, or -1 if no match."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/join.rs

@@ -26,7 +26,7 @@ impl Command for StrJoin {
     }
 
     fn usage(&self) -> &str {
-        "Concatenate multiple strings into a single string, with an optional separator between each"
+        "Concatenate multiple strings into a single string, with an optional separator between each."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/length.rs

@@ -50,7 +50,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Output the length of any strings in the pipeline"
+        "Output the length of any strings in the pipeline."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/replace.rs

@@ -57,7 +57,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Find and replace text"
+        "Find and replace text."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/reverse.rs

@@ -27,7 +27,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Reverse every string in the pipeline"
+        "Reverse every string in the pipeline."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/starts_with.rs

@@ -43,7 +43,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "Check if an input starts with a string"
+        "Check if an input starts with a string."
     }
 
     fn search_terms(&self) -> Vec<&str> {

crates/nu-command/src/strings/str_/trim/trim_.rs

@@ -60,7 +60,7 @@ impl Command for SubCommand {
             )
     }
     fn usage(&self) -> &str {
-        "Trim whitespace or specific character"
+        "Trim whitespace or specific character."
     }
 
     fn search_terms(&self) -> Vec<&str> {