Fix an exception that could occur when typing "/" by itself in autocomplete and a regular tag starting with "/" was returned. This caused an exception in `r[:antecedent].length` because the tag's antecedent was nil.
Fix an exception that could occur when typing "/" by itself in autocomplete and a regular tag starting with "/" was returned. This caused an exception in `r[:antecedent].length` because the tag's antecedent was nil.