[cms] Translatable attributes are escaped twice

[trev]

How to reproduce

Put the following code on a Markdown page:

{{string Some <a href="{{string-link http://example.com/?foo&bar}}">link</a>}}

Observed behaviour

The following code is being generated:

Some <a href="http://example.com/?foo&amp;amp;bar">link</a>

Note that the ampersand is being escaped twice.

Expected behaviour

The following code should be generated:

Some <a href="http://example.com/?foo&amp;bar">link</a>

[trev]

Fixed: ​https://hg.adblockplus.org/cms/rev/41d0ce2575ef

[Ross]

Fixed.

Tested by:
Adding provided example to a CMS page and checking the output.

cms / r42