---- markdown ----
Some text with&mdash;entities in it&mdash;.  We can try uglier things like
&amp;mdash; or &&&; and see what happens.  We can also add more than one
entity &amp;&amp;&mdash;&amp; in a row.

This is an &unknown; entity and should be left untouched.

And these are raw &#x2014; &#2014; Unicode code points.

---- gplus ----
Some text with—entities in it—. We can try uglier things like &mdash; or &&&; and see what happens. We can also add more than one entity &&—& in a row.

This is an &unknown; entity and should be left untouched.

And these are raw — ߞ Unicode code points.
