search: improve literal parentheses interpretation

Created by: rvantonder

Previously a literal pattern like repo:foo Args or main) wouldn't work as expected. This was interpreted as "Args" or (concat "main" ")"), and concat implies a space separation, meaning "main )" instead of "main)". Instead, the intuitive interpretation is that the dangling right parenthesis should be merged above, to be "main)", which is what this PR does.

We cannot always interpret things in this natural way: there simply are ambiguous cases that are currently too tricky to handle once such a pattern is combined with groups, like (respObj.Size and (data))) (is the second to last parenthesis trying to close the group, and a typo happened? or is the second pattern intentionally meant to be (data))?). For such tricky cases we just return a friendly error message for now. In future we can consider suggestions.