plugin info alter hook needs to be documented in api.php file

Please check the attached patch file.

Good start, thanks!
I've made a few comments. But also, please can you work with an MR rather than post patches?

1. +++ b/localgov_waste_collection.api.php
   @@ -0,0 +1,20 @@
   + *   plugin_id => $plugin_definition.
   

   We don't normally define arrays with => like that, but instead say what the key and the value are. You can just say 'keyed by the plugin ID' here.

2. +++ b/localgov_waste_collection.api.php
   @@ -0,0 +1,20 @@
   +{
   

   The { is on the wrong line, and this needs sample code -- you can crib from one of those other hooks I mentioned. It can be something simple like changing the label.