Move validate and set attribute into append an attribute

dom.bs

@@ -6366,10 +6366,13 @@ given a <var>document</var>, <var>localName</var>, <var>namespace</var>, and opt
 </ol>
 
 <p>To <dfn export id=concept-element-attributes-append lt="append an attribute">append</dfn> an
-<a>attribute</a> <var>attribute</var> to an <a for=/>element</a> <var>element</var>, run these
-steps:
+<a>attribute</a> <var>attribute</var> to an <a for=/>element</a> <var>element</var>, with
+<var>sink</var>, run these steps:
 
 <ol>
+ <li><p><a>Validate and set attribute value</a> <var>attribute</var>'s <a for="Attr">value</a> for
+ <var>attribute</var> with <var>element</var>, and <var>sink</var>.
+
  <li><p><a for=list>Append</a> <var>attribute</var> to <var>element</var>'s
  <a for=Element>attribute list</a>.
 
@@ -6486,13 +6489,18 @@ and a string <var>sink</var>:
 
  <li><p>If <var>oldAttr</var> is <var>attr</var>, return <var>attr</var>.
 
- <li><p><a>Validate and set attribute value</a> <var>newAttr</var>'s <a for="Attr">value</a> for
- <var>newAttr</var> with <var>element</var>, and <var>sink</var>.
+ <li>
+  <p>If <var>oldAttr</var> is non-null, then:</p>
 
- <li><p>If <var>oldAttr</var> is non-null, then <a lt="replace an attribute">replace</a>
- <var>oldAttr</var> with <var>attr</var>.
+ <ul>
+ <li><p><a>Validate and set attribute value</a> <var>attr</var>'s <a for="Attr">value</a> for
+ <var>attr</var> with <var>element</var>, and <var>sink</var>.
 
- <li><p>Otherwise, <a lt="append an attribute">append</a> <var>attr</var> to <var>element</var>.
+ <li><p><a lt="replace an attribute">Replace</a> <var>oldAttr</var> with <var>attr</var>.
+ </ul>
+
+ <li><p>Otherwise, <a lt="append an attribute">append</a> <var>attr</var> to <var>element</var>
+ with <var>sink</var>.
 
  <li><p>Return <var>oldAttr</var>.
 </ol>
@@ -6509,21 +6517,12 @@ or string <var>namespace</var> (default null), and an optional string <var>sink<
  <a lt="get an attribute by namespace and local name">getting an attribute</a> given
  <var>namespace</var>, <var>localName</var>, and <var>element</var>.
 
- <li>
- <p>If <var>attribute</var> is null, then:
- <ol>
- <li><p>Set <var>attribute</var> to a new <a>attribute</a> whose <a for=Attr>namespace</a> is
- <var>namespace</var>, <a for=Attr>namespace prefix</a> is <var>prefix</var>,
- <a for=Attr>local name</a> is <var>localName</var> and <a for=Node>node document</a> is
- <var>element</var>'s <a for=Node>node document</a>.
-
- <li><p><a>Validate and set attribute value</a> <var>value</var> for <var>attribute</var> with
- <var>element</var>, and <var>sink</var>.
-
- <li><p><a lt="append an attribute">Append</a> <var>attribute</var> to <var>element</var>.
-
- <li><p>Return.
- </ol>
+ <li>If <var>attribute</var> is null, create an <a>attribute</a> whose <a for=Attr>namespace</a> is
+ <var>namespace</var>, <a for=Attr>namespace prefix</a> is <var>prefix</var>,
+ <a for=Attr>local name</a> is <var>localName</var>, <a for=Attr>value</a> is <var>value</var>, and
+ <a for=Node>node document</a> is <var>element</var>'s <a for=Node>node document</a>, then
+ <a lt="append an attribute">append</a> this <a>attribute</a> to <var>element</var> with
+ <var>sink</var>, and then return.
 
  <li><p><a lt="change an attribute">Change</a> <var>attribute</var> to <var>value</var>, with <var>sink</var>.
 </ol>
@@ -6786,21 +6785,11 @@ method steps are:
  and null otherwise.
  <!-- This is step 2 of "get an attribute by name", modified as appropriate -->
 
- <li>
- <p>If <var>attribute</var> is null, then:
-
- <ol>
- <li><p>Set <var>attribute</var> to a new <a>attribute</a> whose <a for=Attr>local name</a> is
- <var>qualifiedName</var> and <a for=Node>node document</a> is <a>this</a>'s
- <a for=Node>node document</a>.
-
- <li><p><a>Validate and set attribute value</a> <var>value</var> for <var>attribute</var>,
- with <a>this</a> and "Element setAttribute".
-
- <li><p><a lt="append an attribute">Append</a> <var>attribute</var> to <a>this</a>.
-
- <li><p>Return.
- </ol>
+ <li><p>If <var>attribute</var> is null, create an <a>attribute</a> whose
+ <a for=Attr>local name</a> is <var>qualifiedName</var>, <a for=Attr>value</a> is
+ <var>value</var>, and <a for=Node>node document</a> is <a>this</a>'s <a for=Node>node document</a>,
+ then <a lt="append an attribute">append</a> this <a>attribute</a> to <a>this</a> with
+ "Element setAttribute", and then return.
 
  <li><p><a lt="change an attribute">Change</a> <var>attribute</var> to <var>value</var>, with "Element setAttribute".
 </ol>
@@ -6863,8 +6852,8 @@ method steps are:
  <li><p>If <var>force</var> is not given or is true, create an <a>attribute</a> whose
  <a for=Attr>local name</a> is <var>qualifiedName</var>, <a for=Attr>value</a> is the empty
  string, and <a for=Node>node document</a> is <a>this</a>'s <a for=Node>node document</a>, then
- <a lt="append an attribute">append</a> this <a>attribute</a> to <a>this</a>, and then return
- true.
+ <a lt="append an attribute">append</a> this <a>attribute</a> to <a>this</a> with
+ "Element toggleAttribute", and then return true.
 
  <li><p>Return false.
  </ol>