Support redo after autoformat changes buffer

[notpeter]

trafficstars

Summary

Zed should (where possible) leverage CRDT to support redoing after a formatter has changed a buffer.

Description

Steps to reproduce:

1. Create a file a.yaml with this as contents: foo: {a:b}
2. At the end of the line type # foo and then undo (cmd-z)
3. Save (with formatting) which will change the file to:

   foo: { a:b }
   

4. Attempt to redo (cmd-shift-z) to restore the comment. Nothing happens.

See also:

• https://github.com/zed-industries/zed/issues/17455
• https://github.com/zed-industries/zed/discussions/31021
• https://github.com/zed-industries/zed/discussions/31307
• https://github.com/zed-industries/zed/issues/31917