[Tails-dev] [review'n'merge] new link for enigmail howto

hello!

The Enigmail Howto link at 'OpenPGP encryption with Enigmail' is broken in:

https://tails.boum.org/doc/anonymous_internet/thunderbird/


I have replaced it with another Quick Start Guide, I hope it was the same.

Please review:

repo: https://git-tails.immerda.ch/emmapeel/tails/
branch: new_enigmail_howto


Two commits: first is the change, second the .PO refresh and unfuzzy.

https://git-tails.immerda.ch/emmapeel/tails/log/?h=new_enigmail_howto