feat: add solidity support (#178)

Solidity docs: docs.soliditylang.org/en/latest/layout-of-source-files.html#comments

Author: alefbragin

lua/Comment/ft.lua

@@ -78,6 +78,7 @@ local L = {
     scala = { M.cxx_l, M.cxx_b },
     scheme = { M.lisp_l, M.lisp_b },
     sh = { M.hash },
+    solidity = { M.cxx_l, M.cxx_b },
     sql = { M.dash, M.cxx_b },
     stata = { M.cxx_l, M.cxx_b },
     svelte = { M.html, M.html },