"Video element auditory content has captions" [f51b46]: Adding 1.2.1 …

…as a secondary requirement. (#2089)

* Adding 1.2.1 as a secondary requirement.

* Modifying secondary requirement text to be the standard format.

_rules/video-captions-f51b46.md

@@ -20,6 +20,8 @@ accessibility_requirements:
     failed: not satisfied
     passed: further testing needed
     inapplicable: further testing needed
+  wcag20:1.2.1: # Audio-only and Video-only (Prerecorded) (A)
+    secondary: This success criterion is **less strict** than this rule. This is because the rule does not consider that the video may be a media alternative for text. Some of the failed examples satisfy this success criterion.
 input_aspects:
   - DOM Tree
   - CSS Styling