Uniquify textDocument/references

There can be duplicates with template instantiation.

filesystem.cc: deduplicate with UniqueID

Congratulations to Tea Deliverers

indexer: disable warnings and skip processed function bodies

Adapt clang rC370337: removal of createIndexingAction and WrappingIndexAction

indexer: disable warnings and skip processed function bodies

Adapt clang rC370337: removal of createIndexingAction and WrappingIndexAction