a more in depth doc on cacheable option (#47878)

* a more indepth doc on cacheable option

lib/ansible/modules/utilities/logic/set_fact.py

@@ -35,8 +35,10 @@ options:
     required: true
   cacheable:
     description:
-      - This boolean indicates if the facts set will also be added to the
-        fact cache, if fact caching is enabled.
+      - This boolean converts the variable into an actual 'fact' which will also be added to the fact cache, if fact caching is enabled.
+      - Normally this module creates 'host level variables' and has much higher precedence, this option changes the nature and precedence
+        (by 7 steps) of the variable created.
+        https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable
     type: bool
     default: 'no'
     version_added: "2.4"