## Summary

Filenames containing markdown syntax (e.g. `__somefile__`, `*somefile*`)
were being rendered as formatted text in the git discard confirmation
dialog.

Follow-up to #55697 for the git discard confirmation path mentioned in
#53060.

## Changes

Wrapped the git discard confirmation filename with `MarkdownInlineCode`
in `git_panel.rs`, so special markdown characters like `_`, `*`, and `[`
render literally.

## Testing

Added `test_discard_prompt_escapes_markdown_in_file_name` in
`git_panel.rs` to verify filenames with markdown special characters
render literally in the discard confirmation dialog.

Run:
```bash
cargo test -p git_ui test_discard_prompt_escapes_markdown_in_file_name
```

Release Notes:

- Fixed file names containing markdown special characters (e.g.
`__somefile__`) being rendered as formatted text in the git discard
confirmation dialog.