Add word wrapping mode (#3597)

* feat: add word wrapping mode for --wrap flag

* Run `cargo fmt` and add CHANGELOG entry

* Add word wrap tests, update manpage and shell completions

- Add integration tests for word wrapping: basic word boundary breaking,
  fallback to character wrapping for long words, line numbers, and
  short lines that fit without wrapping
- Update manpage to document the new 'word' wrapping mode
- Update bash, fish, zsh, and PowerShell completions with 'word' option
- Avoid unnecessary clone of `line_buf` when word wrap is disabled

* make clippy and cargo fmt happy

---------

Co-authored-by: Keith Hall <keith-hall@users.noreply.github.com>

assets/completions/_bat.ps1.in

@@ -9,7 +9,7 @@ Register-ArgumentCompleter -Native -CommandName '{{PROJECT_EXECUTABLE}}' -Script
     $ArrayCompletion = @('bash', 'fish', 'zsh', 'ps1')
     $ArrayWhen       = @('auto', 'never', 'always')
     $ArrayYesNo      = @('never', 'always')
-    $ArrayWrap       = @('always', 'never', 'character')
+    $ArrayWrap       = @('always', 'never', 'character', 'word')
     $ArrayBinary     = @('no-printing', 'as-text')
     $ArrayPrint      = @('unicode', 'caret')
 
@@ -135,7 +135,7 @@ Register-ArgumentCompleter -Native -CommandName '{{PROJECT_EXECUTABLE}}' -Script
             [CompletionResult]::new('--file-name'             , 'file-name'             , [CompletionResultType]::ParameterName, 'Specify the name to display for a file.')
             [CompletionResult]::new('--diff-context'          , 'diff-context'          , [CompletionResultType]::ParameterName, 'diff-context')
             [CompletionResult]::new('--tabs'                  , 'tabs'                  , [CompletionResultType]::ParameterName, 'Set the tab width to T spaces.')
-            [CompletionResult]::new('--wrap'                  , 'wrap'                  , [CompletionResultType]::ParameterName, 'Specify the text-wrapping mode (*auto*, character).')
+            [CompletionResult]::new('--wrap'                  , 'wrap'                  , [CompletionResultType]::ParameterName, 'Specify the text-wrapping mode (*auto*, never, character, word).')
             [CompletionResult]::new('--terminal-width'        , 'terminal-width'        , [CompletionResultType]::ParameterName, 'Explicitly set the width of the terminal instead of determining it automatically. If prefixed with ''+'' or ''-'', the value will be treated as an offset to the actual terminal width. See also: ''--wrap''.')
             [CompletionResult]::new('--color'                 , 'color'                 , [CompletionResultType]::ParameterName, 'When to use colors (*auto*, never, always).')
             [CompletionResult]::new('--italic-text'           , 'italic-text'           , [CompletionResultType]::ParameterName, 'Use italics in output (always, *never*)')