Correct <template>.content getter steps

Also address some variable naming issues nearby.

Fixes #11953.

Author: annevk

source

@@ -68013,11 +68013,11 @@ interface <dfn interface>HTMLTemplateElement</dfn> : <span>HTMLElement</span> {
   contents</span>:</p>
 
   <ol>
-   <li><p>Let <var>doc</var> be the <code>template</code> element's <span>node document</span>'s <span>appropriate template contents owner
-   document</span>.</p></li>
+   <li><p>Let <var>document</var> be the <code>template</code> element's <span>node
+   document</span>'s <span>appropriate template contents owner document</span>.</p></li>
 
    <li><p>Create a <code>DocumentFragment</code> object whose <span>node document</span> is
-   <var>doc</var> and <span data-x="concept-DocumentFragment-host">host</span> is the
+   <var>document</var> and <span data-x="concept-DocumentFragment-host">host</span> is the
    <code>template</code> element.</p></li>
 
    <li><p>Set the <code>template</code> element's <span>template contents</span> to the newly
@@ -68026,33 +68026,34 @@ interface <dfn interface>HTMLTemplateElement</dfn> : <span>HTMLElement</span> {
   </div>
 
   <div algorithm>
-  <p>A <code>Document</code> <var>doc</var>'s <dfn>appropriate template contents owner
+  <p>A <code>Document</code> <var>document</var>'s <dfn>appropriate template contents owner
   document</dfn> is the <code>Document</code> returned by the following algorithm:</p>
 
   <ol>
    <li>
-    <p>If <var>doc</var> is not a <code>Document</code> created by this algorithm, then:</p>
+    <p>If <var>document</var> is not a <code>Document</code> created by this algorithm:</p>
 
     <ol>
      <li>
-      <p>If <var>doc</var> does not yet have an <dfn>associated inert template document</dfn>,
-      then:</p>
+      <p>If <var>document</var> does not yet have an <dfn>associated inert template
+      document</dfn>:</p>
 
       <ol>
-       <li><p>Let <var>new doc</var> be a new <code>Document</code> (whose <span
+       <li><p>Let <var>newDocument</var> be a new <code>Document</code> (whose <span
        data-x="concept-document-bc">browsing context</span> is null). This is "a
        <code>Document</code> created by this algorithm" for the purposes of the step above.</p></li>
 
-       <li><p>If <var>doc</var> is an <span data-x="HTML documents">HTML document</span>, mark
-       <var>new doc</var> as an <span data-x="HTML documents">HTML document</span>
+       <li><p>If <var>document</var> is an <span data-x="HTML documents">HTML document</span>, then
+       mark <var>newDocument</var> as an <span data-x="HTML documents">HTML document</span>
        also.</p></li>
 
-       <li><p>Set <var>doc</var>'s <span>associated inert template document</span> to <var>new doc</var>.</p></li>
+       <li><p>Set <var>document</var>'s <span>associated inert template document</span> to
+       <var>newDocument</var>.</p></li>
       </ol>
      </li>
 
-     <li><p>Set <var>doc</var> to <var>doc</var>'s <span>associated inert
-     template document</span>.</p></li>
+     <li><p>Set <var>document</var> to <var>document</var>'s <span>associated inert template
+     document</span>.</p></li>
     </ol>
 
     <p class="note">Each <code>Document</code> not created by this algorithm thus gets a single
@@ -68063,7 +68064,7 @@ interface <dfn interface>HTMLTemplateElement</dfn> : <span>HTMLElement</span> {
     <code>Document</code> owner for their contents.</p>
    </li>
 
-   <li><p>Return <var>doc</var>.</p></li>
+   <li><p>Return <var>document</var>.</p></li>
   </ol>
   </div>
 
@@ -68074,23 +68075,29 @@ interface <dfn interface>HTMLTemplateElement</dfn> : <span>HTMLElement</span> {
 
   <ol>
    <li>
-    <p>Let <var>doc</var> be <var>node</var>'s <span>node document</span>'s
+    <p>Let <var>document</var> be <var>node</var>'s <span>node document</span>'s
     <span>appropriate template contents owner document</span>.</p>
 
     <p class="note"><var>node</var>'s <span>node document</span> is the <code>Document</code> object
     that <var>node</var> was just adopted <em>into</em>.</p>
    </li>
 
    <li><p><span data-x="concept-node-adopt">Adopt</span> <var>node</var>'s
-   <span>template contents</span> (a <code>DocumentFragment</code> object) into <var>doc</var>.</p></li>
+   <span>template contents</span> (a <code>DocumentFragment</code> object) into
+   <var>document</var>.</p></li>
   </ol>
   </div>
 
   <div algorithm>
   <p>The <dfn attribute for="HTMLTemplateElement"><code
-  data-x="dom-template-content">content</code></dfn> getter steps are to return
-  <code>template</code>'s <span>template contents</span>, if the <span>template contents</span> is
-  not a <code>ShadowRoot</code> node; otherwise null.</p>
+  data-x="dom-template-content">content</code></dfn> getter steps are:
+
+  <ol>
+   <li><p><span>Assert</span>: <span>this</span>'s <span>template contents</span> is not a
+   <code>ShadowRoot</code> node.</p></li>
+
+   <li><p>Return <span>this</span>'s <span>template contents</span>.</p></li>
+  </ol>
   </div>
 
   <div algorithm>
@@ -140369,7 +140376,7 @@ document.body.appendChild(text);
          <li><p>Set <var>shadow</var>'s <span
          data-x="concept-shadow-root-declarative">declarative</span> to true.</p></li>
 
-         <li><p>Set <var>template</var>'s <span>template contents</span> property to
+         <li><p>Set <var>template</var>'s <span>template contents</span> to
          <var>shadow</var>.</p></li>
 
          <li><p>Set <var>shadow</var>'s <span>available to element internals</span> to