Current filter factory rules are very relaxed, anything that doesn't match filter syntax perfectly is passed down to the fuzzy filter, that happily accepts every input and doesn't complain. This change makes syntax checks more strict, we explicitly look for roughly <anything><any of the chars used as operators><anything> (in reality we match the first <anything> used filter specific regex, but that can still be any regex) and only if evaluated filter expression doesn't match this regex we pass it to the fuzzy filter. Once we have a match we check if operator is supported by the filter and we're more strict there, in case of a===b we currently accept = as the operator and ==b as the value, now operator will be === (as we match for any of the operator chars in use) and fail once that doesn't match.
