Makefile example: Add known failures

examples/prism-makefile.html

@@ -263,4 +263,14 @@ <h2>Complete example</h2>
             > tmp.dir/$$X ; done
         cd tmp.dir ; zoo aM ../tar.zoo *
         -rm -rf tmp.dir
-</code></pre>
+</code></pre>
+
+<h2>Known failures</h2>
+<p>There are certain edge cases where Prism will fail.
+    There are always such cases in every regex-based syntax highlighter.
+    However, Prism dares to be open and honest about them.
+    If a failure is listed here, it doesn’t mean it will never be fixed. This is more of a “known bugs” list, just with a certain type of bug.
+</p>
+
+<h3>Comment-like substring</h3>
+<pre><code>"foo # bar";</code></pre>