handle autofocus like nonce and tabindex for #258

Author: davidcarlisle

spec.html

@@ -360,6 +360,7 @@ Global Attributes
             elements:
           p>
           <ul>
+            <li><a><code>autofocuscode>a>li>
             <li><a><code>classcode>a>li>
             <li><a><code>data-*code>a>li>
             <li><a><code>dircode>a>li>
@@ -384,13 +385,15 @@ Attributes common to HTML and MathML elements
             <dfn class="element-attr no-export">classdfn>,
             <dfn class="element-attr no-export">styledfn>,
             <dfn class="no-export"><code>data-*code>dfn>,
+            <dfn class="element-attr no-export">autofocusdfn> and
             <dfn class="element-attr no-export">noncedfn> and
             <dfn class="element-attr no-export">tabindexdfn>
             attributes have the same syntax and semantics as defined for
             [^global/id^],
             [^global/class^],
 	    [^html-global/style^],
             <a data-cite="HTML/../#embedding-custom-non-visible-data-with-the-data-*-attributes">data-*a>,
+            [^htmlsvg-global/autofocus^],
             [^htmlsvg-global/nonce^] and
             [^htmlsvg-global/tabindex^]
             attributes on HTML elements.