To implement `select:symbol.enum` filters, we look at each symbol's
ctags 'kind' and check if it matches the filter value `enum`. We
accidentally didn't include 'enum' in this match logic, so all these
symbols were filtered away.
This PR fixes that, and adds a few improvements:
* Use a shared map between `symbol.LSPKind` and `symbol.SelectKind`, to
avoid drift between these two conversions.
* Audit the ctags mapping from
[sourcegraph/zoekt#674](https://github.com/sourcegraph/zoekt/pull/674)
and add other missing kinds (besides enum)
Closes SPLF-178