[bat] Make #region folding markers case-insensitive for REM

[Copilot]

Batch folding markers currently only matched uppercase REM, so region folding failed for common rem/Rem comment styles in case-insensitive CMD scripts. This change updates Bat region marker matching to accept all REM case variants (with optional @) while preserving existing :: behavior.

• Scope

  • Update extensions/bat/language-configuration.json folding marker regexes for start and end.

• Behavior change

  • #region / #endregion now match:
    • REM ...
    • rem ...
    • Rem ...
    • @REM ... / @rem ...
    • :: ... (unchanged)

• Regex update

  "folding": {
    "markers": {
      "start": "^\\s*(::|@?[Rr][Ee][Mm])\\s*#region",
      "end": "^\\s*(::|@?[Rr][Ee][Mm])\\s*#endregion"
    }
  }

[Copilot]

Pull request overview

This PR updates the batch (bat) language configuration’s folding marker regex so that #region / #endregion folding works for common case variants of REM comments in Windows CMD scripts, while keeping existing :: comment folding behavior intact.

Changes:

• Adjust batch folding marker patterns to match REM in a case-insensitive way (including optional leading @).
• Preserve the existing ::-based folding marker support.

Show a summary per file

File	Description
extensions/bat/language-configuration.json	Updates folding marker regexes so region folding recognizes rem/Rem/REM and @rem variants.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0