docs: re-order default providers to match default config

README.md

@@ -67,7 +67,7 @@
     -- elsewhere in your config, without redefining it, via `opts_extend`
     sources = {
       completion = {
-        enabled_providers = { 'snippets', 'lsp', 'buffer', 'path' },
+        enabled_providers = { 'lsp', 'path', 'snippets', 'buffer' },
       },
     },