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/formats/from/command.rs

@@ -12,7 +12,7 @@ impl Command for From {
     }
 
     fn usage(&self) -> &str {
-        "Parse a string or binary data into structured data"
+        "Parse a string or binary data into structured data."
     }
 
     fn signature(&self) -> nu_protocol::Signature {

crates/nu-command/src/formats/from/json.rs

@@ -14,7 +14,7 @@ impl Command for FromJson {
     }
 
     fn usage(&self) -> &str {
-        "Convert from json to structured data"
+        "Convert from json to structured data."
     }
 
     fn signature(&self) -> nu_protocol::Signature {

crates/nu-command/src/formats/from/nuon.rs

@@ -13,7 +13,7 @@ impl Command for FromNuon {
     }
 
     fn usage(&self) -> &str {
-        "Convert from nuon to structured data"
+        "Convert from nuon to structured data."
     }
 
     fn signature(&self) -> nu_protocol::Signature {

crates/nu-command/src/formats/to/command.rs

@@ -12,7 +12,7 @@ impl Command for To {
     }
 
     fn usage(&self) -> &str {
-        "Translate structured data to a format"
+        "Translate structured data to a format."
     }
 
     fn signature(&self) -> nu_protocol::Signature {

crates/nu-command/src/formats/to/csv.rs

@@ -56,7 +56,7 @@ impl Command for ToCsv {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into .csv text "
+        "Convert table into .csv text ."
     }
 
     fn run(

crates/nu-command/src/formats/to/html.rs

@@ -144,11 +144,11 @@ impl Command for ToHtml {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into simple HTML"
+        "Convert table into simple HTML."
     }
 
     fn extra_usage(&self) -> &str {
-        "Screenshots of the themes can be browsed here: https://github.com/mbadolato/iTerm2-Color-Schemes"
+        "Screenshots of the themes can be browsed here: https://github.com/mbadolato/iTerm2-Color-Schemes."
     }
 
     fn run(

crates/nu-command/src/formats/to/md.rs

@@ -32,7 +32,7 @@ impl Command for ToMd {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into simple Markdown"
+        "Convert table into simple Markdown."
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/formats/to/toml.rs

@@ -19,7 +19,7 @@ impl Command for ToToml {
     }
 
     fn usage(&self) -> &str {
-        "Convert record into .toml text"
+        "Convert record into .toml text."
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/formats/to/tsv.rs

@@ -28,7 +28,7 @@ impl Command for ToTsv {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into .tsv text"
+        "Convert table into .tsv text."
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/formats/to/xml.rs

@@ -51,7 +51,7 @@ impl Command for ToXml {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into .xml text"
+        "Convert table into .xml text."
     }
 
     fn run(

crates/nu-command/src/formats/to/yaml.rs

@@ -19,7 +19,7 @@ impl Command for ToYaml {
     }
 
     fn usage(&self) -> &str {
-        "Convert table into .yaml/.yml text"
+        "Convert table into .yaml/.yml text."
     }
 
     fn examples(&self) -> Vec<Example> {