Allow for aliassing certain file types, to convert to a type with treesitter highlighting.

I chose bash for a replacement for sh, since it seemed to be the closest
out of all options. Which makes sence, since it is the bourne again
shell.

.config/nvim/lua/plugin/nvim-treesitter.lua

@@ -6,16 +6,31 @@ return { {
 	lazy = false,
 	config = function()
 		-- Pre-install a few languages we're (very) likely going to use
-		require('nvim-treesitter').install({
+		local ts = require('nvim-treesitter')
+		ts.install({
 			'c', 'make',
 			'bash', 'gitignore', 'editorconfig',
 			'ini', 'json', 'yaml',
 		})
+
+		-- Define aliases for entries that lack an entry, but should have one.
+		local alias = {
+			{ 'sh',    'bash' },
+		}
+
+		local pat = vim.iter(alias):map(function(a) return a[1] end):totable()
+		vim.list_extend(pat, ts.get_available())
 		Autocmd('FileType', {
-			pattern = require('nvim-treesitter').get_available(),
-			callback = function(ft)
-				require('nvim-treesitter').install(ft.match)
+			pattern = pat,
+			callback = function(arg)
+				local a = vim.iter(alias)
+				    :find(function(a) return arg.match == a[1] end)
+				if not a then -- Ensure we only install if an alias was found
+					require('nvim-treesitter').install(vim.bo.ft)
 					pcall(vim.treesitter.start)
+					return
+				end
+				vim.bo.ft = a[2] -- Retriggers function
 			end
 		})
 	end,