Editorial: address various nits

In particular:

* Adjusted case (“wiki”—should otherwise be qualified for more clarity)
* Rephrased “microformats wiki existing-rel-values page” (super-long, reads awkwardly)
* Added article to make `source` element conditions more readable
* Limited repetition (double “and so forth”)

source

@@ -14693,7 +14693,7 @@ interface <dfn interface>HTMLMetaElement</dfn> : <span>HTMLElement</span> {
    <dt>Specification</dt>
 
    <dd>A link to a more detailed description of the metadata name's semantics and requirements. It
-   could be another page on the Wiki, or a link to an external page.</dd>
+   could be another page on the wiki, or a link to an external page.</dd>
 
 
    <dt>Synonyms</dt>
@@ -23217,7 +23217,7 @@ document.body.appendChild(wbr);</code></pre>
 
   <p><span w-dev subdfn data-x="dom-a-rellist"></span>The <dfn element-attr for="a,area"><code
   data-x="attr-hyperlink-rel">rel</code></dfn> attribute on <code>a</code> and <code>area</code>
-  elements controls what kinds of links the elements create. The attribute's value must be a
+  elements controls what kinds of links the elements create. The attribute's value must be an
   <span>unordered set of unique space-separated tokens</span>. The <a href="#linkTypes">allowed
   keywords and their meanings</a> are defined below.</p>
 
@@ -25821,11 +25821,11 @@ document.body.appendChild(wbr);</code></pre>
   <h5>Other link types</h5>
 
   <p><dfn data-x="concept-rel-extensions">Extensions to the predefined set of link types</dfn> may
-  be registered in the <a
+  be registered on the <a
   href="https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions">microformats
-  wiki existing-rel-values page</a>. <ref spec=MFREL></p>
+  page for existing rel values</a>. <ref spec=MFREL></p>
 
-  <p>Anyone is free to edit the <span data-x="">microformats wiki existing-rel-values page</span> at
+  <p>Anyone is free to edit the <span data-x="">microformats page for existing rel values</span> at
   any time to add a type. Extension types must be specified with the following information:</p>
 
   <dl>
@@ -25924,7 +25924,7 @@ document.body.appendChild(wbr);</code></pre>
    <dt>Specification</dt>
 
    <dd><p>A link to a more detailed description of the keyword's semantics and requirements. It
-   could be another page on the Wiki, or a link to an external page.</p></dd>
+   could be another page on the wiki, or a link to an external page.</p></dd>
 
 
    <dt>Synonyms</dt>
@@ -25978,23 +25978,23 @@ document.body.appendChild(wbr);</code></pre>
 
   <div w-nodev>
 
-  <p>Conformance checkers must use the information given on the <span data-x="">microformats wiki
-  existing-rel-values page</span> to establish if a value is allowed or not: values defined in this
+  <p>Conformance checkers must use the information given on the <span data-x="">microformats page
+  for existing rel values</span> to establish if a value is allowed or not: values defined in this
   specification or marked as "proposed" or "ratified" must be accepted when used on the elements for
   which they apply as described in the "Effect on..." field, whereas values marked as "discontinued"
   or not listed in either this specification or on the aforementioned page must be rejected as
   invalid. Conformance checkers may cache this information (e.g. for performance reasons or to avoid
   the use of unreliable network connectivity).</p>
 
-  <p>When an author uses a new type not defined by either this specification or the Wiki page,
-  conformance checkers should offer to add the value to the Wiki, with the details described above,
+  <p>When an author uses a new type not defined by either this specification or the wiki page,
+  conformance checkers should offer to add the value to the wiki, with the details described above,
   with the "proposed" status.</p>
 
   </div>
 
   <p>Types defined as extensions in the <a
   href="https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions">microformats
-  wiki existing-rel-values page</a> with the status "proposed" or "ratified" may be used with the
+  page for existing rel values</a> with the status "proposed" or "ratified" may be used with the
   <code data-x="">rel</code> attribute on <code>link</code>, <code>a</code>, and <code>area</code>
   elements in accordance to the "Effect on..." field. <ref spec=MFREL></p>
 
@@ -26450,7 +26450,7 @@ interface <dfn interface>HTMLSourceElement</dfn> : <span>HTMLElement</span> {
   element or a <span>media element</span>:</p>
 
   <dl class="switch">
-   <dt><code>source</code> element's parent is a <code>picture</code> element</dt>
+   <dt>The <code>source</code> element's parent is a <code>picture</code> element</dt>
 
    <dd>
     <p>The <dfn element-attr for="source" data-x="attr-source-srcset"><code>srcset</code></dfn>
@@ -26502,7 +26502,7 @@ interface <dfn interface>HTMLSourceElement</dfn> : <span>HTMLElement</span> {
     <p>The <code data-x="attr-source-src">src</code> attribute must not be present.</p>
    </dd>
 
-   <dt><code>source</code> element's parent is a <span>media element</span></dt>
+   <dt>The <code>source</code> element's parent is a <span>media element</span></dt>
 
    <dd>
     <p>The <dfn element-attr for="source"><code data-x="attr-source-src">src</code></dfn> attribute
@@ -26768,7 +26768,7 @@ interface <dfn interface>HTMLImageElement</dfn> : <span>HTMLElement</span> {
   animated bitmaps (APNGs, animated GIFs), animated vector graphics (XML files with an SVG
   <span>document element</span> that use declarative SMIL animation), and so forth. However, these
   definitions preclude SVG files with script, multipage PDF files, interactive MNG files, HTML
-  documents, plain text documents, and so forth. <ref spec=PNG> <ref spec=GIF> <ref spec=JPEG> <ref
+  documents, plain text documents, and the like. <ref spec=PNG> <ref spec=GIF> <ref spec=JPEG> <ref
   spec=PDF> <ref spec=XML> <ref spec=APNG> <ref spec=SVG> <ref spec=MNG> </p>
 
   <p>The <code data-x="attr-img-srcset">srcset</code> attribute may also be present, and is a