Enforce required, optional, and rest positional arguments start with an uppercase and end with a period. (#11285)

# Description

This updates all the positional arguments (except with
`--features=dataframe` or `--features=extra`) to start with an uppercase
letter and end with a period.

Part of #5066, specifically [this
comment](/nushell/nushell/issues/5066#issuecomment-1421528910)

Some arguments had example data removed from them because it also
appears in the examples.

There are other inconsistencies in positional arguments I noticed while
making the tests pass which I will bring up in #5066.

# User-Facing Changes

Positional arguments are now consistent

# Tests + Formatting

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting

Automatic documentation updates

crates/nu-command/src/conversions/into/binary.rs

@@ -44,7 +44,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/bool.rs

@@ -29,7 +29,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/datetime.rs

@@ -104,7 +104,7 @@ impl Command for SubCommand {
             .rest(
             "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/duration.rs

@@ -36,7 +36,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/filesize.rs

@@ -49,7 +49,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/float.rs

@@ -31,7 +31,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .allow_variants_without_examples(true)
             .category(Category::Conversions)

crates/nu-command/src/conversions/into/int.rs

@@ -81,7 +81,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .category(Category::Conversions)
     }

crates/nu-command/src/conversions/into/string.rs

@@ -52,7 +52,7 @@ impl Command for SubCommand {
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
-                "for a data structure input, convert data at the given cell paths",
+                "For a data structure input, convert data at the given cell paths.",
             )
             .named(
                 "decimals",