Fix reference edge-case

lib/rules_block/reference.js

@@ -144,6 +144,17 @@ module.exports = function reference(state, startLine, _endLine, silent) {
   // skip trailing spaces until the rest of the line
   while (pos < max && str.charCodeAt(pos) === 0x20/* space */) { pos++; }
 
+  if (pos < max && str.charCodeAt(pos) !== 0x0A) {
+    if (title) {
+      // garbage at the end of the line after title,
+      // but it could still be a valid reference if we roll back
+      title = '';
+      pos = destEndPos;
+      lines = destEndLineNo;
+      while (pos < max && str.charCodeAt(pos) === 0x20/* space */) { pos++; }
+    }
+  }
+
   if (pos < max && str.charCodeAt(pos) !== 0x0A) {
     // garbage at the end of the line
     return false;

test/fixtures/commonmark/bad.txt

@@ -67,22 +67,6 @@ error:
 </blockquote>
 
 
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 2479
-
-.
-[foo]: /url
-"title" ok
-.
-<p>&quot;title&quot; ok</p>
-.
-
-error:
-
-<p>[foo]: /url
-&quot;title&quot; ok</p>
-
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 4737
 

test/fixtures/commonmark/good.txt

@@ -2062,6 +2062,16 @@ src line: 2471
 <p>[foo]: /url &quot;title&quot; ok</p>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 2479
+
+.
+[foo]: /url
+"title" ok
+.
+<p>&quot;title&quot; ok</p>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 2489