Tag auto-complete using XFES 1.3.0

• Require StandardLib v1.21.0+
• Require Search Improvements v2.15.4+
• XF2.3 support, requires XF2.3.3+

• Fix deleted tags where not removed from the search index if deleted by having no usage for non-permanent tags

• Fix search index was not updated when extending Forum Tag Filtering add-on correctly

• Require StandardLib v1.19.0+
• Require Search Improvements 2.12.0+
• Add "Max tag autocomplete results" option
• Add "Use fuzzy matching for tag autocomplete" option
  • To revert to previous matching behavior, set this option to an empty value
• Adjust tag autocomplete to better handle typos and variations

• Fix accidental dependency on an internal add-on which results in tag autocomplete failing for public users

• Require Standard Library by Xon v1.18.0+
• Code cleanup to be more extensible
• If using Search Improvements v2.11.0+, Tag autocomplete now prefers prefix matches
  • Recommend updating Search Improvements to v2.11.0+