comment out rb and rtc

closes #115

While this PR fills in mappings for `rb` and the `rtc` elements based on how they are presently mapped, they are also being commented out as they are marked as obsolete in the HTML specification.

If consensus can be reached on adding these elements back into the HTML specification, then this PR should be reversed.

Author: scottaohara

index.html

@@ -2762,27 +2762,43 @@ HTML Element Role Mappings
                 td>
                 <td class="comments">td>
             tr>
+            
             <tr tabindex="-1" id="el-rp">
                 <th><a data-cite="HTML">`rp`a>th>
                 <td class="aria">No corresponding roletd>
@@ -2836,15 +2852,44 @@ HTML Element Role Mappings
                 td>
                 <td class="comments">td>
             tr>
-            <tr tabindex="-1" id="el-rtc">
-                <th><a href="https://w3c.github.io/html/textlevel-semantics.html#the-rtc-element"><code>rtccode>a>th>
+            
             <tr tabindex="-1" id="el-ruby">
                 <th><a data-cite="HTML">`ruby`a>th>
                 <td class="aria">No corresponding roletd>
@@ -6306,10 +6351,11 @@ Change Log
         <section>
           <h4>Substantive changes since moving entirely to the Web Application Working Group (formerly Web Platform WG) (01-Oct-2016)h4>
           <ul>
-            <li>18-Sept-2019: Update `mark` element's UIA `LocalizedControlType` and AX `AXRoleDescription`.  See <a href="https://github.com/w3c/html-aam/issues/236">GitHub issue 236a>.li>
+            <li>22-Sept-2019: Remove mappings for `rb` and `rtc` elements as they are marked as obsolete in HTML. See <a href="https://github.com/w3c/html-aam/issues/115">GitHub issue #115a> and <a href="https://github.com/w3c/html-aam/pull/252">pull request #253a>.
+            <li>18-Sept-2019: Update `mark` element's UIA `LocalizedControlType` and AX `AXRoleDescription`. See <a href="https://github.com/w3c/html-aam/issues/236">GitHub issue 236a>.li>
             <li>18-Sept-2019: Update ATK mappings for `summary` and `details` elements. See <a href="https://github.com/w3c/html-aam/issues/142">GitHub issue #142a> and <a href="https://github.com/w3c/html-aam/issues/147">GitHub issue #147a>.li>
             <li>18-Sept-2019: Update MSAA mappings for `sub` and `sup`. See <a href="https://github.com/w3c/html-aam/pull/252">GitHub pull request #252a>.li>
-            <li>11-Sept-2019: Update mapping for `menu` to match <a data-cite="html/#the-menu-element">HTML Living Standarda>. Remove element and attribute mappings that are not applicable to `menu` and `menuitem`.  Update mapping of `menu` to `role="list"`. See <a href="https://github.com/w3c/html-aam/issues/188">GitHub issue #188a>.li>
+            <li>11-Sept-2019: Update mapping for `menu` to match <a data-cite="html/#the-menu-element">HTML Living Standarda>. Remove element and attribute mappings that are not applicable to `menu` and `menuitem`. Update mapping of `menu` to `role="list"`. See <a href="https://github.com/w3c/html-aam/issues/188">GitHub issue #188a>.li>
             <li>10-July-2019: Further updated mappings for `ins` and `del` elements. See <a href="https://github.com/w3c/html-aam/pull/219">GitHub pull request #219a>.li>
             <li>13-June-2019: Update mappings for `ins` and `del` elements. See <a href="https://github.com/w3c/html-aam/issues/141">GitHub issue #141a>.li>
             <li>10-June-2019: Update ATK mappings for `header` and `footer` when not scoped to the `body`. See <a href="https://github.com/w3c/html-aam/issues/129">GitHub issue #129a>.li>