feat(ft): add coq support (#388)

See https://coq.github.io/doc/v8.9/refman/language/gallina-specification-language.html

Author: Halbaroth

lua/Comment/ft.lua

@@ -50,6 +50,7 @@ local L = setmetatable({
     cmake = { M.hash, M.hash_bracket },
     conf = { M.hash },
     conkyrc = { M.dash, M.dash_bracket },
+    coq = { M.fsharp_b },
     cpp = { M.cxx_l, M.cxx_b },
     cs = { M.cxx_l, M.cxx_b },
     css = { M.cxx_b, M.cxx_b },