Search: convert structural search patterns to zoekt queries
Created by: rvantonder
This PR:
-
Adds scaffolding for the structural search code path. The
patterntype:structural
option will case out (a) the code path for converting structural search patterns to Zoekt patterns for indexed search and (b) the code path for searcher to run structural search. -
Adds the functionality for (a) above, and converts structural (comby) patterns to Zoekt queries for indexed search. The resulting Zoekt queries are (only) a conjunction of substrings. The intent is for Zoekt to return only the files that satisfy this pattern. The results are not used yet.
Test plan: Added tests for converting structural queries to Zoekt patterns. No end-to-end yet, because the other end isn't done yet.