Closes#32205
The issue was that in some places the end of the replacement range used
anchors with `Bias::Left` instead of `Bias::Right`. Before #31872
completions were recomputed on every change and so the anchor bias
didn't matter. After that change, the end anchor didn't move as the
user's typing. Changing it to `Bias::Right` to "stick" to the character
to the right of the cursor fixes this.
Release Notes:
- Fixes incorrect auto-completion of `/files` in text threads (Preview
Only)