Editorial: rely more on Infra in the data: URL processor

Author: annevk

fetch.bs

@@ -8075,7 +8075,7 @@ that RFC's normative processing requirements to be compatible with deployed cont
  <li><p>Let <var>input</var> be the result of running the <a>URL serializer</a> on
  <var>dataURL</var> with <a for="URL serializer"><i>exclude fragment</i></a> set to true.
 
- <li><p>Remove the leading "<code>data:</code>" string from <var>input</var>.
+ <li><p>Remove the leading "<code>data:</code>" from <var>input</var>.
 
  <li><p>Let <var>position</var> point at the start of <var>input</var>.
 
@@ -8098,6 +8098,7 @@ that RFC's normative processing requirements to be compatible with deployed cont
  <li>
   <p>If <var>mimeType</var> ends with U+003B (;), followed by zero or more U+0020 SPACE, followed by
   an <a>ASCII case-insensitive</a> match for "<code>base64</code>", then:
+  <!-- This really needs an ASCII case-insensitive ends with. -->
 
   <ol>
    <li><p>Let <var>stringBody</var> be the <a>isomorphic decode</a> of <var>body</var>.
@@ -8110,11 +8111,11 @@ that RFC's normative processing requirements to be compatible with deployed cont
 
    <li><p>Remove trailing U+0020 SPACE <a>code points</a> from <var>mimeType</var>, if any.
 
-   <li><p>Remove the last U+003B (;) <a>code point</a> from <var>mimeType</var>.
+   <li><p>Remove the last U+003B (;) from <var>mimeType</var>.
   </ol>
 
- <li><p>If <var>mimeType</var> starts with U+003B (;), then prepend "<code>text/plain</code>"
- to <var>mimeType</var>.
+ <li><p>If <var>mimeType</var> <a for=string>starts with</a> "<code>;</code>", then prepend
+ "<code>text/plain</code>" to <var>mimeType</var>.
 
  <li><p>Let <var>mimeTypeRecord</var> be the result of <a lt="parse a MIME type">parsing</a>
  <var>mimeType</var>.