* Add the TLA+ language
This patch adds support for the TLA+ specification language.
https://github.com/search?utf8=%E2%9C%93&q=MODULE+extension%3Atla&type=Code&ref=searchresults
* Update TLA grammar license
Attribution is given in the license since the grammar is based off of the TLA+ language developed by Microsoft and HP.
* Sort languages.yml alphabetically
* Removing duplicate entry
