Implements word wrap for function signatures (or any other long single item hint list)
Makes reformatting code hints explicit.

Adds a handleWideResults to hint responses (only active for function signature hints right now).
The CodeHintList changes the styling and behavior a bit to suit.
Clarify the "availableWidth" formula per review comment.
Merge pull request #3916 from adobe/dangoor/3610-long-sig

Implements word wrap for function signatures (merging after fixing "minor comment" from @redmunds).