added doc notes about vars plugins in precedence

docs/docsite/rst/playbooks_variables.rst

@@ -858,14 +858,17 @@ In 2.x, we have made the order of precedence more specific (with the last listed
 
   * role defaults [1]_
   * inventory file or script group vars [2]_
-  * inventory group_vars/all
-  * playbook group_vars/all
-  * inventory group_vars/*
-  * playbook group_vars/*
+  * inventory group_vars/all [3]_
+  * playbook group_vars/all [3]_
+  * inventory group_vars/* [3]_
+  * playbook group_vars/* [3]_
   * inventory file or script host vars [2]_
   * inventory host_vars/*
   * playbook host_vars/*
-  * host facts / cached set_facts [3]_
+  * host facts / cached set_facts [4]_
+  * inventory host_vars/* [3]_
+  * playbook host_vars/* [3]_
+  * host facts
   * play vars
   * play vars_prompt
   * play vars_files
@@ -884,7 +887,8 @@ Basically, anything that goes into "role defaults" (the defaults folder inside t
 
 .. [1] Tasks in each role will see their own role's defaults. Tasks defined outside of a role will see the last role's defaults.
 .. [2] Variables defined in inventory file or provided by dynamic inventory.
-.. [3] When created with set_facts's cacheable option, variables will have the high precedence in the play,
+.. [3] Includes vars added by 'vars plugins' as well as host_vars and group_vars which are added by the default vars plugin shipped with Ansible.
+.. [4] When created with set_facts's cacheable option, variables will have the high precedence in the play,
        but will be the same as a host facts precedence when they come from the cache.
 
 .. note:: Within any section, redefining a var will overwrite the previous instance.