add: tidy up the code, more modular

lua/user/utils/lsp.lua

@@ -0,0 +1,16 @@
+local M = {}
+
+M.list_registered_providers_names = function(filetype)
+	local s = require("null-ls.sources")
+	local available_sources = s.get_available(filetype)
+	local registered = {}
+	for _, source in ipairs(available_sources) do
+		for method in pairs(source.methods) do
+			registered[method] = registered[method] or {}
+			table.insert(registered[method], source.name)
+		end
+	end
+	return registered
+end
+
+return M