Cleanup handling of suggest command.

* Moves magic number to the top of file.
* Reports the length limit back to the user.
* Cleaned up !s, !suggest command match so it doesn't accidentally match !something else.
* Trim whitespace from suggestions (start/end, whitespace runs).
* Fixes some jslint warnings.

(We have to get at least one regex in this code or John will never be happy.)