Merge #8510 #8533

8510: Move cursor position when using item movers r=jonas-schievink a=jonas-schievink

This updates the cursor position when moving items around to stay in the same location within the moved node.

I changed the `moveItem` response to `SnippetTextEdit[]`, since that made more sense to me (the file was ignored by the client anyways, since the edits always apply to the current document). It also matches `onEnter`, which seems logical to me, but please let me know if this doesn't make sense.

There's still a bug in the client-side snippet code that will cause the cursor position to be slightly off when moving parameters in the same line (presumably we don't track the column correctly after deleting `$0`). Not really sure how to fix that immediately, but this PR should already be an improvement despite that bug.

8533: Fix typo in style guide r=jonas-schievink a=jonas-schievink

Fixes bold text rendering

bors r+

Co-authored-by: Jonas Schievink <[email protected]>