Make unicode backslach completion fuzzy and case insensitive Ok, the fuzzy part is super simple. - candidates matching prefix - If no matches: names that contain the string - If no matches :whether each part of the string split on space is contained in the name of the unicode character. That is to say, `\GREEK OMICRON<tab>` will search whether both GREEK and and OMICRON (case insensitive) are available, in the worst case scenario This allows things like `\omicron` to give you proper suggestions. `\nu` will give you latex nu, `\greek nu` with match as the prefix of `GREEK NUMERAL ...` `\Nu` will match all the `... NUMERAL...` in unicode, but `\Nu greek` will limit the searches enough Mitigate #13514