Improve performance in `skipToken` when maxNesting is exceeded

lib/parser_inline.js

@@ -93,6 +93,19 @@ ParserInline.prototype.skipToken = function (state) {
 
       if (ok) { break; }
     }
+  } else {
+    // Too much nesting, just skip until the end of the paragraph.
+    //
+    // NOTE: this will cause links to behave incorrectly in the following case,
+    //       when an amount of `[` is exactly equal to `maxNesting + 1`:
+    //
+    //       [[[[[[[[[[[[[[[[[[[[[foo]()
+    //
+    // TODO: remove this workaround when CM standard will allow nested links
+    //       (we can replace it by preventing links from being parsed in
+    //       validation mode)
+    //
+    state.pos = state.posMax;
   }
 
   if (!ok) { state.pos++; }

lib/presets/default.js

@@ -29,7 +29,7 @@ module.exports = {
     //
     highlight: null,
 
-    maxNesting:   20            // Internal protection, recursion limit
+    maxNesting:   100            // Internal protection, recursion limit
   },
 
   components: {

test/misc.js

@@ -281,7 +281,7 @@ describe('maxNesting', function () {
     var md = markdownit({ maxNesting: 2 });
     assert.strictEqual(
       md.render('[[[[[[[[[[[[[[[[[[foo]()'),
-      '<p>[[[[[[[[[[[[[[[[[<a href="">foo</a></p>\n'
+      '<p>[[[[[[[[[[[[[[[[[[foo]()</p>\n'
     );
   });