Formatting CONTRIBUTING.md to 80 colums
Formatting CONTRIBUTING.md to 80 colums

Added a little paragraph about how to contribute to Godot's translations

(cherry picked from commit 4f874e4f8ef3393eb1d0b8241b7ef7f70a18119a
and synced with master text)

pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1