docs: add note about needing to restart for global commands to be pic…

…ked up (#5582) [skip ci]

docs/content/users/extend/custom-commands.md

@@ -59,6 +59,8 @@ tail -f /opt/solr/server/logs/solr.log
 
 Global commands work exactly the same as project-level commands, but they need to go in your *global* `.ddev` directory. Your home directory has a `.ddev/commands` in it, where you can add host, web, or db commands.
 
+Changes to the command files in the global `.ddev` directory need a `ddev start` for changes to be picked up by a project, as the global commands are copied to the project on start.
+
 ## Shell Command Examples
 
 There are many examples of [global](https://github.com/ddev/ddev/tree/master/pkg/ddevapp/global_dotddev_assets/commands) and [project-level](https://github.com/ddev/ddev/tree/master/pkg/ddevapp/dotddev_assets/commands) custom/shell commands that ship with DDEV you can adapt for your own use. They can be found in your `~/.ddev/commands/*` directories and in your project’s `.ddev/commands/*` directories. There you’ll see how to provide usage, examples, and how to use arguments provided to the commands. For example, the [`xdebug` command](https://github.com/ddev/ddev/blob/master/pkg/ddevapp/global_dotddev_assets/commands/web/xdebug) shows simple argument processing and the [launch command](https://github.com/ddev/ddev/blob/master/pkg/ddevapp/global_dotddev_assets/commands/host/launch) demonstrates flag processing.