3892: Add L_DOLLAR for TYPE_RECOVERY_SET r=matklad a=edwin0cheng This PR is a hot fix for issue #3861 that just prevent it make the parser being stuck. The actual problem described in https://github.com/rust-analyzer/rust-analyzer/pull/3873#issuecomment-610208693 is a very deep rabbit hole I don't want to dig right now :( Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>