nvim: Update nushell lsp installation

Nushell lsp is now integrated directly into the 'nu' command. This
update stops mason from trying to install a 'nushell' LSP and simply
activates the nu-internal LSP if it finds the correct executable
instead.

nvim/.config/nvim/lua/core/languages.lua

@@ -7,9 +7,12 @@
 -- with their respective names used by lspconfig, nvim-treesitter, nvim-lint and conform.
 --
 
-local nushell = { lsp = { nushell = {} }, ts = { "nu" } }
-if vim.fn.executable("nufmt") == 1 then
-	nushell.format = { nu = { "nufmt" } }
+local nushell = function()
+	local nushell = { ts = { "nu" } } -- nushell lsp directly built into `nu` cmd
+	if vim.fn.executable("nufmt") == 1 then
+		nushell.format = { nu = { "nufmt" } }
+	end
+	return nushell
 end
 
 -- FIXME: This does not work for populating LSP config,
@@ -96,7 +99,7 @@ local languages = {
 		format = { markdown = { "prettier", "injected" } },
 	},
 	nim = { lsp = { nim_langserver = {} }, ts = { "nim", "nim_format_string" }, format = { nim = { "nimpretty" } } },
-	nu = nushell,
+	nu = nushell(),
 	python = {
 		lsp = { basedpyright = {}, ruff = {} },
 		ts = { "python" },

nvim/.config/nvim/lua/plugins/lsp.lua

@@ -83,6 +83,10 @@ local lsp = {
 				end
 			end
 
+			if vim.fn.executable("nu") == 1 then
+				register("nushell")
+			end
+
 			register("marksman", {
 				filetypes = { "markdown", "quarto" },
 				on_attach = function(client, _)