unwanted ; appended at the end of some messages when using quotes

As reported by @fkautz at https://github.com/gitterHQ/gitter/issues/612:

Example output: in each case, no ; was ever typed: "one" "github.com/example/two"; "one.two/three"; "http://github.com/example/one"

The problem appears to be that "github.com/example/two" becomes &quot;github.com/example/two&quot;, which then gets incorrectly autolinked to &quot;<a href="....">github.com/example/two&quot</a>;