remove unused explcit_semantic_role

Author: shunguoy

_rules/aria-required-owned-element-bc4a75.md

@@ -45,7 +45,7 @@ The applicability of this rule is limited to the [WAI-ARIA 1.2 Recommendation][w
 
 ### Assumptions
 
-If the [explicit semantic role][] on the target element is incorrectly used, and any relationships between elements are already programmatically determinable, failing this rule may not result in accessibility issues for users of assistive technologies, and it should then not be considered a failure under [WCAG success criterion 1.3.1 Info and Relationships](https://www.w3.org/TR/WCAG22/#info-and-relationships).
+If the [semantic role][] on the target element is incorrectly used, and any relationships between elements are already programmatically determinable, failing this rule may not result in accessibility issues for users of assistive technologies, and it should then not be considered a failure under [WCAG success criterion 1.3.1 Info and Relationships](https://www.w3.org/TR/WCAG22/#info-and-relationships).
 
 ### Accessibility Support
 
@@ -102,7 +102,7 @@ This element with the `menu` role only owns elements with the `menuitem`, `menui
 
 #### Passed Example 4
 
-This element with the `tablist` role only owns elements with the `tab` role. The `tab` role is one of the [required owned elements][] for `tablist`. The `li` element is ignored because it has an [explicit semantic role][] of `none`.
+This element with the `tablist` role only owns elements with the `tab` role. The `tab` role is one of the [required owned elements][] for `tablist`. The `li` element is ignored because it has an [semantic role][] of `none`.
 
 ```html
 <ul role="tablist">
@@ -345,7 +345,6 @@ This element with the `menu` role has an `aria-busy` attribute set to `true`.
 [required owned elements]: https://www.w3.org/TR/wai-aria-1.2/#mustContain 'Define Required owned element'
 [owns]: #owned-by
 [owned by]: #owned-by
-[explicit semantic role]: #explicit-role
 [semantic role]: #semantic-role
 [included in the accessibility tree]: #included-in-the-accessibility-tree
 [wai-aria 1.2]: https://www.w3.org/TR/wai-aria-1.2/