refactor: Display

[PatelTirth25]

This PR refactors the display_list.rs file, which was over 1700 lines, into a more manageable structure by splitting it into separate modules. (https://github.com/rust-lang/annotate-snippets-rs/issues/184)

Folder structure:

src/renderer/display ├── constants.rs ├── cursor_line.rs ├── display_annotations.rs ├── display_header.rs ├── display_line.rs ├── display_list.rs ├── display_mark.rs ├── display_set.rs ├── display_text.rs ├── end_line.rs └── mod.rs