Remove tooling suggestions for SVG and MathML

These were rather specific for something that HTML does not specify generally. And also resulted in confusion: w3c/mathml#145.

source

@@ -39480,10 +39480,6 @@ interface <dfn>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
   content model was replaced, for the purposes of MathML layout and rendering, by a <span>MathML
   <code>merror</code></span> element containing some appropriate error message.</p>
 
-  <p>To enable authors to use MathML tools that only accept MathML in its XML form, interactive HTML
-  user agents are encouraged to provide a way to export any MathML fragment as an XML
-  namespace-well-formed XML fragment.</p>
-
   </div>
 
   <p>The semantics of MathML elements are defined by <cite>MathML</cite> and <span>other applicable
@@ -39533,14 +39529,6 @@ interface <dfn>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
   <span>phrasing content</span>, <span>flow content</span>, and <span>palpable content</span>
   categories for the purposes of the content models in this specification.</p>
 
-  <div w-nodev>
-
-  <p>To enable authors to use SVG tools that only accept SVG in its XML form, interactive HTML user
-  agents are encouraged to provide a way to export any SVG fragment as an XML namespace-well-formed
-  XML fragment.</p>
-
-  </div>
-
   <p>When the <span>SVG <code>foreignObject</code></span> element contains elements from the
   <span>HTML namespace</span>, such elements must all be <span>flow content</span>.</p>