feat(nvim): Add gitconfig customfiletype

Signed-off-by: Noah Knegt <git@noahknegt.com>

.config/nvim/lua/polish.lua

@@ -1,5 +1,3 @@
-if true then return end -- WARN: REMOVE THIS LINE TO ACTIVATE THIS FILE
-
 -- This will run last in the setup process and is a good place to configure
 -- things like custom filetypes. This just pure lua so anything that doesn't
 -- fit in the normal config locations above can go here
@@ -7,12 +5,6 @@ if true then return end -- WARN: REMOVE THIS LINE TO ACTIVATE THIS FILE
 -- Set up custom filetypes
 vim.filetype.add {
   extension = {
-    foo = "fooscript",
-  },
-  filename = {
-    ["Foofile"] = "fooscript",
-  },
-  pattern = {
-    ["~/%.config/foo/.*"] = "fooscript",
+    gitconfig = "gitconfig",
   },
 }