Fix fences rule

closing fence should not be indented more than 3 spaces

lib/rules_block/fences.js

@@ -55,6 +55,11 @@ module.exports = function fences(state, startLine, endLine, silent) {
 
     if (state.src.charCodeAt(pos) !== marker) { continue; }
 
+    if (state.tShift[nextLine] - state.blkIndent >= 4) {
+      // closing fence should be indented less than 4 spaces
+      continue;
+    }
+
     pos = state.skipChars(pos, marker);
 
     // closing code fence must be at least as long as the opening one

test/fixtures/commonmark/bad.txt

@@ -32,25 +32,6 @@ error:
 <h1>foo #</h1>
 
 
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 1335
-
-.
-```
-aaa
-    ```
-.
-<pre><code>aaa
-    ```
-</code></pre>
-.
-
-error:
-
-<pre><code>aaa
-</code></pre>
-
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 3124
 

test/fixtures/commonmark/good.txt

@@ -1060,6 +1060,19 @@ aaa
 </code></pre>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 1335
+
+.
+```
+aaa
+    ```
+.
+<pre><code>aaa
+    ```
+</code></pre>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 1348