[matchbrackets addon] Treat and null tokes as interchangeable

Closes #6572

Author: marijnh

addon/edit/matchbrackets.js

@@ -38,7 +38,7 @@
     if (config && config.strict && (dir > 0) != (pos == where.ch)) return null;
     var style = cm.getTokenTypeAt(Pos(where.line, pos + 1));
 
-    var found = scanForBracket(cm, Pos(where.line, pos + (dir > 0 ? 1 : 0)), dir, style || null, config);
+    var found = scanForBracket(cm, Pos(where.line, pos + (dir > 0 ? 1 : 0)), dir, style, config);
     if (found == null) return null;
     return {from: Pos(where.line, pos), to: found && found.pos,
             match: found && found.ch == match.charAt(0), forward: dir > 0};
@@ -67,7 +67,8 @@
       if (lineNo == where.line) pos = where.ch - (dir < 0 ? 1 : 0);
       for (; pos != end; pos += dir) {
         var ch = line.charAt(pos);
-        if (re.test(ch) && (style === undefined || cm.getTokenTypeAt(Pos(lineNo, pos + 1)) == style)) {
+        if (re.test(ch) && (style === undefined ||
+                            (cm.getTokenTypeAt(Pos(lineNo, pos + 1)) || "") == (style || ""))) {
           var match = matching[ch];
           if (match && (match.charAt(1) == ">") == (dir > 0)) stack.push(ch);
           else if (!stack.length) return {pos: Pos(lineNo, pos), ch: ch};