home: vim: remove commenting plug-ins

Rely on the new built-in support which was added upstream as part of
v0.10.

Crucially, upstream supports using tree-sitter aware comment strings by default.

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

@@ -1,10 +0,0 @@
-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" })