[clangd] Force Dex to respect symbol collector flags
Dex should utilize FuzzyFindRequest.RestrictForCodeCompletion flags
and omit symbols not meant for code completion when asked for it.
The measurements below were conducted with setting
FuzzyFindRequest.RestrictForCodeCompletion to true (so that it's
more realistic). Sadly, the average latency goes down, I suspect that is
mostly because of the empty queries where the number of posting lists is
|Cumulative query latency (7000 FuzzyFindRequests over LLVM static index)||6182735043 ns||7202442053 ns||+16%|
|Whole Index size||81.24 MB||81.79 MB||+0.6%|
Out of 292252 symbols collected from LLVM codebase 136926 appear to be
restricted for code completion.
Differential Revision: https://reviews.llvm.org/D52357