TLA revisited (#2990)

* 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

lib/linguist/languages.yml

@@ -3531,6 +3531,13 @@ SystemVerilog:
   - .vh
   ace_mode: verilog
 
+TLA:
+  type: programming
+  extensions:
+  - .tla
+  tm_scope: source.tla
+  ace_mode: text
+
 TOML:
   type: data
   extensions: