Apparently, nvim reports its code action kinds using both the actual
strings (e.g. "refactor.extract") and the enumeration names (e.g.
"RefactorExtract"). I don't know why this is done - possibly an attempt
at compatibility with non-compliant server implementations? Regardless,
this was causing a crash on init (when tres tried to parse an
initializaiton message), which is easily fixed by just supporting those
enumeration values.
Resolves: #867
