Editorial: fix wording issue in "replace data"

See https://lists.w3.org/Archives/Public/www-dom/2017JanMar/0012.html.

dom.bs

@@ -4223,7 +4223,7 @@ for an <var>element</var> using <var>namespace</var>, run these steps:
  <li><p>Return null.
 </ol>
 
-<p>To <dfn export>locate a namespace</dfn> for a <var>node</var> using <var>prefix</var> switch on
+<p>To <dfn export>locate a namespace</dfn> for a <var>node</var> using <var>prefix</var>, switch on
 <var>node</var>:
 
 <dl class=switch>
@@ -6760,9 +6760,8 @@ To <dfn export id=concept-cd-replace>replace data</dfn> of node <var>node</var>
  <li>If <var>offset</var> is greater than <var>length</var>, then <a>throw</a> an
  {{IndexSizeError}}.
 
- <li>If <var>offset</var> plus <var>count</var> is greater
- than <var>length</var> let <var>count</var> be
- <var>length</var> minus <var>offset</var>.
+ <li>If <var>offset</var> plus <var>count</var> is greater than <var>length</var>, then set
+ <var>count</var> to <var>length</var> minus <var>offset</var>.
 
  <li><a>Queue a mutation record</a> of "<code>characterData</code>"
  for <var>node</var> with oldValue <var>node</var>'s
@@ -9830,6 +9829,7 @@ Jungkee Song,
 Justin Summerlin,
 呂康豪 (Kang-Hao Lu),
 Kevin Sweeney,
+Kirill Topolyan,
 Koji Ishii,
 Lachlan Hunt,
 Lauren Wood,