regexp: Add missing local for arrays match mbegin mend

See zsh-users#497.

Author: phy1729

highlighters/regexp/regexp-highlighter.zsh

@@ -52,6 +52,7 @@ _zsh_highlight_regexp_highlighter_loop()
   local buf="$1" pat="$2"
   integer OFFSET=0
   local MATCH; integer MBEGIN MEND
+  local -a match mbegin mend
   while true; do
     [[ "$buf" =~ "$pat" ]] || return;
     region_highlight+=("$((MBEGIN - 1 + OFFSET)) $((MEND + OFFSET)) $ZSH_HIGHLIGHT_REGEXP[$pat]")