Use Infra's concatenation definition

Fixes #555.

dom.bs

@@ -219,8 +219,7 @@ object is its first <a>following</a>
 </ol>
 
 <p>The <dfn export id=concept-ordered-set-serializer>ordered set serializer</dfn> takes a
-<var>set</var> and returns the concatenation of the strings in <var>set</var>, separated from each
-other by U+0020, if <var>set</var> is non-empty, and the empty string otherwise.
+<var>set</var> and returns the <a for=string>concatenation</a> of <var>set</var> using U+0020 SPACE.
 
 
 <h3 id=selectors>Selectors</h3>
@@ -4030,7 +4029,7 @@ following, switching on <a>context object</a>:
 <dl class=switch>
  <dt>{{DocumentFragment}}
  <dt>{{Element}}
- <dd>The concatenation of <a for=CharacterData>data</a> of all
+ <dd>The <a for=string>concatenation</a> of <a for=CharacterData>data</a> of all
  the {{Text}} <a>node</a>
  <a>descendants</a> of the
  <a>context object</a>, in
@@ -4097,8 +4096,8 @@ steps for each <a>descendant</a> <a>exclusive <code>Text</code> node</a> <var>no
  <li>If <var>length</var> is zero, then <a for=/>remove</a> <var>node</var> and continue with the
  next <a>exclusive <code>Text</code> node</a>, if any.
 
- <li>Let <var>data</var> be the concatenation of the <a for=CharacterData>data</a> of
- <var>node</var>'s <a>contiguous exclusive <code>Text</code> nodes</a> (excluding itself), in
+ <li>Let <var>data</var> be the <a for=string>concatenation</a> of the <a for=CharacterData>data</a>
+ of <var>node</var>'s <a>contiguous exclusive <code>Text</code> nodes</a> (excluding itself), in
  <a>tree order</a>.
 
  <li><a>Replace data</a> with node <var>node</var>, offset <var>length</var>, count 0, and data
@@ -7176,8 +7175,8 @@ if any, and its <a>contiguous exclusive <code>Text</code> nodes</a>, and <var>no
 <a>contiguous exclusive <code>Text</code> nodes</a>, avoiding any duplicates.
 
 <p>The <dfn export id=concept-child-text-content>child text content</dfn> of a <a>node</a>
-<var>node</var> is the concatenation of the <a for=CharacterData>data</a> of all the {{Text}} node
-<a>children</a> of <var>node</var>, in <a>tree order</a>.
+<var>node</var> is the <a for=string>concatenation</a> of the <a for=CharacterData>data</a> of all
+the {{Text}} node <a>children</a> of <var>node</var>, in <a>tree order</a>.
 
 <p>This and <a lt="other applicable specifications">other specifications</a> may define
 <dfn export id=concept-node-text-change-ext>child text content change steps</dfn> for <a>nodes</a>.
@@ -7277,9 +7276,9 @@ To <dfn export id=concept-text-split lt="split a Text node">split</dfn> a {{Text
 <p>The <dfn method for=Text><code>splitText(<var>offset</var>)</code></dfn> method, when invoked,
 must <a lt="split a Text node">split</a> <a>context object</a> with offset <var>offset</var>.
 
-<p>The <dfn attribute for=Text><code>wholeText</code></dfn> attribute's getter must return a
-concatenation of the <a for=CharacterData>data</a> of the <a>contiguous <code>Text</code> nodes</a>
-of <a>context object</a>, in <a>tree order</a>.
+<p>The <dfn attribute for=Text><code>wholeText</code></dfn> attribute's getter must return the
+<a for=string>concatenation</a> of the <a for=CharacterData>data</a> of the
+<a>contiguous <code>Text</code> nodes</a> of the <a>context object</a>, in <a>tree order</a>.
 
 
 
@@ -8894,11 +8893,9 @@ these steps:
  <a for=CharacterData>data</a> from the
  <a>start offset</a> until the end.
 
- <li>Append to <var>s</var> the concatenation, in
- <a>tree order</a>, of the
- <a for=CharacterData>data</a> of all {{Text}}
- <a>nodes</a> that are <a>contained</a> in
- the <a>context object</a>.
+ <li>Append the <a for=string>concatenation</a> of the <a for=CharacterData>data</a> of all {{Text}}
+ <a>nodes</a> that are <a>contained</a> in the <a>context object</a>, in <a>tree order</a>, to
+ <var>s</var>.
 
  <li>If <a for=Range>end node</a> is a
  {{Text}} <a>node</a>, append to
@@ -10085,6 +10082,7 @@ Manish Goregaokar,
 Manish Tripathi,
 Marcos Caceres,
 Mark Miller,
+Martijn van der Ven,
 Mats Palmgren,
 Mounir Lamouri,
 Michael™ Smith,