This reverts commit 1b3b825c7f.
When debugging git diffs we found that this introduced a re-ordering of
messages sent to the LSP:
* User hits "format"
* Zed adjusts spacing, and sends "spaces changed" to the LSP
* Zed sends "format" to LSP
With the async approach here, the format request can now arrive before
the space changed request.
You can reproduce this with `test_strip_whitespace_and_format_via_lsp`
under some conditions.
Release Notes:
- N/A
a247617d6f