Fix reference link title incorrectly kept when followed by trailing garbage

src/inlines.c

@@ -1495,6 +1495,10 @@ bufsize_t cmark_parse_reference_inline(cmark_mem *mem, cmark_chunk *input,
       if (!skip_line_end(&subj)) {
         return 0;
       }
+      // the previously scanned title turned out to be invalid (it was
+      // followed by trailing garbage instead of the end of the line), so
+      // the reference has no title after all.
+      title = cmark_chunk_literal("");
     } else {
       return 0;
     }

test/regression.txt

@@ -321,3 +321,13 @@ Issue #611:
 <p><foo>text</foo></p>
 ````````````````````````````````
 
+Issue #468: Link reference definition title followed by trailing
+garbage on the same line must not be treated as a title.
+```````````````````````````````` example
+[bla]: /bla
+"The title" garbage
+[bla]
+.
+<p>&quot;The title&quot; garbage
+<a href="/bla">bla</a></p>
+````````````````````````````````