Update special_variables.rst (#80210)

The usage of a glossary on this page will allow linking to a specific special variable, like on the glossary page, e.g.: https://docs.ansible.com/ansible/latest/reference_appendices/glossary.html#term-Idempotency

docs/docsite/rst/reference_appendices/special_variables.rst

@@ -7,6 +7,8 @@ Magic variables
 ---------------
 These variables cannot be set directly by the user; Ansible will always override them to reflect internal state.
 
+.. glossary::
+
     ansible_check_mode
         Boolean that indicates if we are in check mode or not
 
@@ -134,6 +136,8 @@ Facts
 -----
 These are variables that contain information pertinent to the current host (`inventory_hostname`). They are only available if gathered first. See :ref:`vars_and_facts` for more information.
 
+.. glossary::
+
     ansible_facts
         Contains any facts gathered or cached for the `inventory_hostname`
         Facts are normally gathered by the :ref:`setup <setup_module>` module automatically in a play, but any module can return facts.
@@ -151,6 +155,8 @@ Connection variables are normally used to set the specifics on how to execute ac
 Only the common ones are described as each connection/become/shell/etc plugin can define its own overrides and specific variables.
 See :ref:`general_precedence_rules` for how connection variables interact with :ref:`configuration settings<ansible_configuration_settings>`, :ref:`command-line options<command_line_tools>`, and :ref:`playbook keywords<playbook_keywords>`.
 
+.. glossary::
+
     ansible_become_user
         The user Ansible 'becomes' after using privilege escalation. This must be available to the 'login user'.