Closes #49581

Adds a `line_ending` language setting that controls how line endings are
handled for new files and during format/save:

- `detect` (default) — detects existing line endings; new files use the
platform default
- `prefer_lf` / `prefer_crlf` — sets LF or CRLF for new files and files
with no existing convention, while preserving existing files
- `enforce_lf` / `enforce_crlf` — normalizes all line endings to LF or
CRLF on every format/save

The setting can be configured globally, per-language, or via
`.editorconfig`'s `end_of_line` property (which maps to `enforce_lf` /
`enforce_crlf`).

Release Notes:

- Added `line_ending` setting to control how line endings are handled
for new files and normalized on save.
- Added support for `.editorconfig` `end_of_line` property to enforce
line endings.

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Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>