When autocompleting a string (e.g. emit_signal or connect), e.g.
emit_signal('visibility_c')
^
where "^" is the cursor, hitting <tab> would insert an unnecessary
quote, breaking the string:
emit_signal('visibility_changed'')
This commit adds a small lookahead, so the end result will be as the
user probably expected:
emit_signal('visibility_changed')
c329780ea7