clarify allowed content of hgroup

response to whatwg#7829 (review)

Author: stevefaulkner

source

@@ -17081,7 +17081,7 @@ interface <dfn interface>HTMLHeadingElement</dfn> : <span>HTMLElement</span> {
    <dd>Where <span>heading content</span> is expected.</dd>
    <dt><span data-x="concept-element-content-model">Content model</span>:</dt>
    <dd>One <code>h1</code>, <code>h2</code>, <code>h3</code>, <code>h4</code>,
-   <code>h5</code>, <code>h6</code> element, optionally with one or more paragraphs of text, 
+   <code>h5</code>, <code>h6</code> element, optionally with one or more <code>p</code> elements, 
   optionally intermixed with <span>script-supporting elements</span>.</dd>
    <dt><span data-x="concept-element-attributes">Content attributes</span>:</dt>
    <dd><span>Global attributes</span></dd>
@@ -17095,7 +17095,7 @@ interface <dfn interface>HTMLHeadingElement</dfn> : <span>HTMLElement</span> {
 
   <p>The <code>hgroup</code> element has no special meaning at all. It <span>represents</span> its children. 
  The element may be used to group a <code>h1</code>&ndash;<code>h6</code> element, for styling purposes, 
- with one or more paragraphs of text representing its subheading, alternative title, or tagline.</p>
+ with one or more <code>p</code> elements containing text representing its subheading, alternative title, or tagline.</p>
 
   <div class="example">