Update README.md

Author: Zeioth

README.md

@@ -63,3 +63,4 @@ Minimalistic alternative for the plugin `mason-null-ls` with support for externa
 * **Do I need mason for this plugin to work?** Yes.
 * **Will this plugin interfere with my none-ls options?** No.
 * **How is this plugin different from mason-null-ls?** Only a couple things. We add a new feature: support for external sources. We remove a feature: We don't provide commands to manually load/unload sources, as we do it automatically anyway. Aditionally, we aim to keep the code easier to understand and contribute to.
+* **My external none-ls source doesn't load correctly**: The source you pass must be formated like `'<anything-you-want>.<method>.<source-name>'`, as we extract the last two fields to load it. For example `'package_name.subdirectory.formatting.reformat_gherkin'`. So if the external source you are trying to pass come from a repository not formatted that way, just fork it and fix it's directory structure.