Summary:
Previously, a change was made to include the opening parenthesis into the
"identifier regex", so that backend received the function call name for cases
like 'T.lookupOne(B' (to autocomplete columns of table T that start with "B").
Unfortunately, that interferes with common cases like 'SUM($B', since instead
of sending '$B', it is now including the function name.
To properly fix the common case, we need to exclude the function name from the
call, but for lookups we need to include it. ACE's methods aren't flexible
enough to override this logic cleanly, so some monkey-patching was needed.
Test Plan: Added a test case
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3874