feat(builtins): warn on nonexistent method

Author: Jose Alvarez

lua/null-ls/builtins/init.lua

@@ -1,3 +1,4 @@
+local logger = require("null-ls.logger")
 local u = require("null-ls.utils")
 
 local export_tables = {
@@ -14,8 +15,7 @@ for method, table in pairs(export_tables) do
         __index = function(t, k)
             local ok, builtin = pcall(require, string.format("null-ls.builtins.%s.%s", method, k))
             if not ok then
-                u.echo(
-                    "WarningMsg",
+                logger:warn(
                     string.format("failed to load builtin %s for method %s; please check your config", k, method)
                 )
                 return
@@ -29,6 +29,9 @@ end
 
 return setmetatable({}, {
     __index = function(_, k)
+        if not export_tables[k] then
+            logger:warn(string.format("failed to load builtin table for method %s; please check your config", k))
+        end
         return export_tables[k]
     end,
 })