Pontoon: Updated Spanish (es-MX) localization of Pontoon Intro
Pontoon: Updated Spanish (es-MX) localization of Pontoon Intro

Translation authors:
- ariana1995enriquez <ariana1995enriquez@gmail.com>
- Mauricio Navarro Miranda <mautematico@mozilla-mexico.org>
- alex_mayorga <alex_mayorga@yahoo.com>
- Bekhruzbek Ochilov <bekhruzbekochilov@yahoo.com>

jotes/pontoon-intro,mathjazz/pontoon-intro,mathjazz/pontoon-intro,jotes/pontoon-intro,mathjazz/pontoon-intro,jotes/pontoon-intro