Improved Not Found Screen

Added partial matches for the Document/Attachment Does Not Exist suggestions, in addition to the existing stemmed and fuzzy matches, for better results.

We were previously searching using indexed Solr data (stemmed) and also using fuzzy searches (string difference of 2; helps with minor typos), but this did not cover partial matches. Example: "Sandb" is matched by the fuzzy search, since it has a difference of 2 characters ("ox"), but "Sand" is not matched by anything (no stemming and too greater string difference - 3).