Editorial: insert some serial commas and fix some typos

source

@@ -29189,7 +29189,7 @@ interface <dfn interface>HTMLSourceElement</dfn> : <span>HTMLElement</span> {
   data-x="dom-source-src">src</code></dfn>, <dfn attribute for="HTMLSourceElement"><code
   data-x="dom-source-type">type</code></dfn>, <dfn attribute for="HTMLSourceElement"
   data-x="dom-source-srcset"><code>srcset</code></dfn>, <dfn attribute for="HTMLSourceElement"
-  data-x="dom-source-sizes"><code>sizes</code></dfn> and <dfn attribute for="HTMLSourceElement"
+  data-x="dom-source-sizes"><code>sizes</code></dfn>, and <dfn attribute for="HTMLSourceElement"
   data-x="dom-source-media"><code>media</code></dfn> must <span>reflect</span> the respective
   content attributes of the same name.</p>
 
@@ -29606,7 +29606,7 @@ interface <dfn interface>HTMLImageElement</dfn> : <span>HTMLElement</span> {
 
   <p>The <dfn attribute for="HTMLImageElement" data-x="dom-img-alt"><code>alt</code></dfn>, <dfn
   attribute for="HTMLImageElement" data-x="dom-img-src"><code>src</code></dfn>, <dfn attribute
-  for="HTMLImageElement" data-x="dom-img-srcset"><code>srcset</code></dfn> and <dfn attribute
+  for="HTMLImageElement" data-x="dom-img-srcset"><code>srcset</code></dfn>, and <dfn attribute
   for="HTMLImageElement" data-x="dom-img-sizes"><code>sizes</code></dfn> IDL attributes must
   <span>reflect</span> the respective content attributes of the same name.</p>
 
@@ -41251,7 +41251,7 @@ interface <dfn interface>TimeRanges</dfn> {
   zero would have a start equal to zero and an end equal to the duration of the timeline.</p>
 
   <p>The timelines used by the objects returned by the <code
-  data-x="dom-media-buffered">buffered</code>, <code data-x="dom-media-seekable">seekable</code> and
+  data-x="dom-media-buffered">buffered</code>, <code data-x="dom-media-seekable">seekable</code>, and
   <code data-x="dom-media-played">played</code> IDL attributes of <span data-x="media element">media
   elements</span> must be that element's <span>media timeline</span>.</p>
 
@@ -56260,7 +56260,7 @@ interface <dfn interface>HTMLLegendElement</dfn> : <span>HTMLElement</span> {
   default value. If it is false, <span data-x="concept-fe-value">value</span> mirrors the default
   value. If it is true, the default value is ignored.</p>
 
-  <p><code>input</code>, <code>textarea</code> and <code>select</code> elements have a
+  <p><code>input</code>, <code>textarea</code>, and <code>select</code> elements have a
   <dfn>user validity</dfn> boolean. It is initially set to false.</p>
 
   <p>To define the behavior of constraint validation in the face of the <code>input</code>
@@ -58425,7 +58425,7 @@ MIT Room 32-G524
   data-x="attr-fe-autocomplete-country">country</code>" field(s), then the "<code
   data-x="attr-fe-autocomplete-country-name">country-name</code>" field(s) must be filled using a
   human-readable name for the same country.</span> When a user agent fills in multiple fields at
-  once, all fields with the same <span>autofill field name</span>, <span>form owner</span> and
+  once, all fields with the same <span>autofill field name</span>, <span>form owner</span>, and
   <span>autofill scope</span> must be filled with the same value.</p>
 
   <p class="example">Suppose a user agent knows of two phone numbers, +1 555 123 1234 and +1 555 666
@@ -115125,7 +115125,7 @@ enum <dfn enum>DOMParserSupportedType</dfn> {
   <div w-nodev>
 
   <p>The <dfn export>fragment serializing algorithm steps</dfn>, given an <code>Element</code>,
-  <code>Document</code> or <code>DocumentFragment</code> <var>node</var> and a boolean <var>require
+  <code>Document</code>, or <code>DocumentFragment</code> <var>node</var> and a boolean <var>require
   well-formed</var>, are:</p>
 
   <ol>
@@ -119070,7 +119070,7 @@ data:&nbsp;test
   data-x="dom-EventSource-readyState">readyState</code> is <code
   data-x="dom-EventSource-CONNECTING">CONNECTING</code>, and the object has one or more event
   listeners registered for <code data-x="event-open">open</code>, <code
-  data-x="event-message">message</code> or <code data-x="event-error">error</code> events, there must
+  data-x="event-message">message</code>, or <code data-x="event-error">error</code> events, there must
   be a strong reference from the <code>Window</code> or <code>WorkerGlobalScope</code> object that
   the <code>EventSource</code> object's constructor was invoked from to the <code>EventSource</code>
   object itself.</p>
@@ -123239,7 +123239,7 @@ interface <dfn interface>Storage</dfn> {
   </ol>
 
   <p>The <dfn method for="Storage"><code data-x="dom-Storage-setItem">setItem(<var>key</var>,
-  <var>value</var>)</code></dfn> method are:</p>
+  <var>value</var>)</code></dfn> method steps are:</p>
 
   <ol>
    <li><p>Let <var>oldValue</var> be null.</p></li>
@@ -126915,7 +126915,7 @@ dictionary <dfn dictionary>StorageEventInit</dfn> : <span>EventInit</span> {
   <p>A <span data-x="syntax-charref">character reference</span> is said to be <dfn
   data-x="charref-in-attribute">consumed as part of an attribute</dfn> if the <var data-x="return
   state">return state</var> is either <span>attribute value (double-quoted) state</span>,
-  <span>attribute value (single-quoted) state</span> or <span>attribute value (unquoted)
+  <span>attribute value (single-quoted) state</span>, or <span>attribute value (unquoted)
   state</span>.</p>
 
   <p>When a state says to <dfn>flush code points consumed as a character reference</dfn>, it means
@@ -139615,7 +139615,7 @@ interface <dfn interface>HTMLParamElement</dfn> : <span>HTMLElement</span> {
   attribute for="HTMLTableElement"><code data-x="dom-table-frame">frame</code></dfn>, <dfn attribute
   for="HTMLTableElement"><code data-x="dom-table-summary">summary</code></dfn>, <dfn attribute
   for="HTMLTableElement"><code data-x="dom-table-rules">rules</code></dfn>, and <dfn attribute
-  for="HTMLTableElement"><code data-x="dom-table-width">width</code></dfn>, IDL attributes of the
+  for="HTMLTableElement"><code data-x="dom-table-width">width</code></dfn> IDL attributes of the
   <code>table</code> element must <span>reflect</span> the respective content attributes of the same
   name.</p>
 
@@ -139659,7 +139659,7 @@ interface <dfn interface>HTMLParamElement</dfn> : <span>HTMLElement</span> {
 
   <p>The <dfn attribute for="HTMLTableSectionElement"><code
   data-x="dom-tbody-vAlign">vAlign</code></dfn> IDL attribute of the <code>tbody</code>,
-  <code>thead</code>, and <code>tfoot</code> element must <span>reflect</span> the elements' <code
+  <code>thead</code>, and <code>tfoot</code> elements must <span>reflect</span> the elements' <code
   data-x="attr-tbody-valign">valign</code> content attributes.</p>
 
   <hr>