csharp: Extract to zed-extensions/csharp repository (#26166)

This PR extracts the C# extension to the
[zed-extensions/csharp](https://github.com/zed-extensions/csharp)
repository.

Release Notes:

- N/A

Marshall Bowers committed 1y ago

431727fdd777194140518b206196d8234b571b11

Parent: cee98f8

Committed by GitHub <noreply@github.com> on 3/5/2025, 10:23:49 PM