Improve shared session tooltip (#16514)

* improve shared session tooltip

* improve language

* the

* improve text

* improvements

administrator/language/en-GB/en-GB.com_config.ini

@@ -194,7 +194,7 @@ COM_CONFIG_FIELD_SESSION_HANDLER_DESC="The mechanism by which Joomla identifies
 COM_CONFIG_FIELD_SESSION_HANDLER_LABEL="Session Handler"
 COM_CONFIG_FIELD_SESSION_TIME_DESC="Auto log out a User after they have been inactive for the entered number of minutes. Do not set too high."
 COM_CONFIG_FIELD_SESSION_TIME_LABEL="Session Lifetime"
-COM_CONFIG_FIELD_SHARED_SESSION_DESC="When enabled, a user's session is shared between the frontend and administrator sections of the site. Note that changing this value will invalidate all existing sessions on the site."
+COM_CONFIG_FIELD_SHARED_SESSION_DESC="When enabled, a user's session is shared between the frontend and administrator sections of the site. Note that changing this value will invalidate all existing sessions on the site. This is not available when the \"Force HTTPS\" option is set to \"Administrator Only\"."
 COM_CONFIG_FIELD_SHARED_SESSION_LABEL="Shared Sessions"
 COM_CONFIG_FIELD_SITE_DISPLAY_MESSAGE_DESC="Display or not a Frontend message when the site is offline. The custom offline message uses the value defined in the 'Custom message' field. The language offline message uses the value defined in the site language ini file."
 COM_CONFIG_FIELD_SITE_DISPLAY_MESSAGE_LABEL="Offline Message"