Add missing maxLength parameter documentation in CrossChunkMatcher.cs

[Copilot]

Addresses review feedback from #1648 to add missing XML documentation for the maxLength parameter.

• Added <param name="maxLength"> tag to the ReplaceAll method documentation

/// <param name="builder">The StringBuilder to search and modify</param>
/// <param name="maxLength">Maximum length of patterns to search for</param>
/// <param name="context">User context passed to callbacks</param>

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