[docs] activity other purpose documentation

Author: ferranrecio

docs/apis/plugintypes/mod/_files/lib_description.md

@@ -61,22 +61,22 @@ function [modname]_supports($feature) {
 
 :::tip
 
-To have your Activity plugin classified in the right Activity category, you must define the function `[modname]_supports` and add the `FEATURE_MOD_PURPOSE` constant:
+To have your Activity plugin classified in the right Activity category, you must define the function `[modname]_supports` and add the `FEATURE_MOD_PURPOSE` constant.
+
+Optionally, if your plugin fits in a secondary purpose, you should add the `FEATURE_MOD_OTHERPURPOSE` constant as well.
 
 <details>
   <summary>View example</summary>
   <div>
 
 ```php
 function [modname]_supports(string $feature) {
-    switch ($feature) {
-        [...]
-        case FEATURE_MOD_PURPOSE:
-            return MOD_PURPOSE_XXXXXX;
-
-        default:
-            return null;
-    }
+    return match ($feature) {
+        // The rest of features should be listed here...
+        FEATURE_MOD_PURPOSE => MOD_PURPOSE_COLLABORATION,
+        FEATURE_MOD_OTHERPURPOSE => MOD_PURPOSE_COMMUNICATION, // Could be omitted if not needed.
+        default => null,
+    };
 }
 ```
 

docs/devupdate.md

@@ -9,6 +9,17 @@ tags:
 
 This page highlights the important changes that are coming in Moodle 5.1 for developers.
 
+## Activity modules: now activities can define a secondary purpose
+
+<Since version="5.1" issueNumber="MDL-85598" />
+
+From now on, activity modules can define two different features in their `PLUGINNAME_supports` function:
+
+- `FEATURE_MOD_PURPOSE`: This is the mandatory main activity purpose, and also the one that will determine the activity's icon color.
+- `FEATURE_MOD_OTHERPURPOSE`: An optional secondary purpose to be used as an extra category in the activity chooser modal.
+
+See the [Activity module support functions](./apis/plugintypes/mod#activity-module-support-functions) for further information.
+
 ## Code Structure
 
 <Since version="5.1" issueNumber="MDL-83424" />