search: friendlier alert for missing operands
Created by: rvantonder
Stacked on #9881.
A query like repo:foo or or or
is ambiguous and no heuristics apply, so an error "Expected operand at " is shown. This PR replaces the debug message with the friendlier alert.
Side note: repo:foo (or or or)
, implied by the alert suggestion, is fine. In future we could consider just running this query and showing the alert with it parenthesized, or add a heuristic that suggests this. See #9745