Mention JSON schema (#2893)

docs/Config.md

@@ -16,6 +16,21 @@ If you want to change the config directory:
 
 - MacOS: `export XDG_CONFIG_HOME="$HOME/.config"`
 
+JSON schema is available for `config.yml` so that IntelliSense in Visual Studio Code
+(completion and error checking) is automatically enabled when the [YAML Red Hat][yaml]
+extension is installed. However, note that automatic schema detection only works
+if your config file is in one of the standard paths mentioned above. If you
+override the path to the file, you can still make IntelliSense work by adding
+
+```yaml
+# yaml-language-server: $schema=https://json.schemastore.org/lazygit.json
+```
+
+to the top of your config file or via [Visual Studio Code settings.json config][settings].
+
+[yaml]: https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml
+[settings]: https://github.com/redhat-developer/vscode-yaml#associating-a-schema-to-a-glob-pattern-via-yamlschemas
+
 ## Default
 
 ```yaml