home: vim: use actual lua files

Since most of the settings are actually just lua in a VimL file.

home/vim/after/plugin/mappings/commentary.lua

@@ -0,0 +1,10 @@
+local wk = require("which-key")
+
+local keys = {
+    name = "Comment/uncomment",
+    c = "Current line",
+    u = "Uncomment the current and adjacent commented lines",
+    ["gc"] = "Uncomment the current and adjacent commented lines",
+}
+
+wk.register(keys, { prefix = "gc" })