Copilot Summary

This pull request includes several updates to the src/diff.rs file to enhance the handling of file diffs, particularly for renamed files. The changes ensure that content diffs are correctly processed and displayed for various file operations. The most important changes include adding content handling for renamed files, updating the FileDiff enum, and modifying the impl FileDiff methods to support these enhancements.

Enhancements to file diff handling:

• src/diff.rs: Modified ChunkDiff to provide a more descriptive error message when encountering an unexpected diff line.
• src/diff.rs: Updated the FileDiff enum to include an optional content field for renamed files.
• src/diff.rs: Enhanced the chunks method in impl FileDiff to handle content for renamed files.
• src/diff.rs: Added content parsing logic for renamed files in the parse_with_similarity_index method. [1] [2]

Improvement to diff summary display:

• src/widget_diff_tree.rs: Updated the DiffTreeNodeContent implementation for FileDiff to include a summary of content changes for renamed files.