Meta: fix markup now that Bikeshed supports mixins (#499)

References #450.

index.bs

@@ -1237,7 +1237,7 @@ that declares state and behavior that can be [=included=] by one or more [=inter
 and that are exposed by objects that implement an [=interface=]
 that [=includes=] the [=interface mixin=].
 
-<pre class="webidl" class="syntax">
+<pre highlight="webidl" class="syntax">
     interface mixin identifier {
       /* mixin_members... */
     };
@@ -1273,7 +1273,7 @@ All of the [=interface mixin member|members=] that appear on each of the [=parti
 are considered to be [=members=] of the [=interface mixin=] itself,
 and—by extension—of the [=interfaces=] that [=include=] the [=interface mixin=].
 
-<pre class="webidl" class="syntax">
+<pre highlight="webidl" class="syntax">
     interface mixin <mark>SomeMixin</mark> {
       /* mixin_members... */
     };
@@ -1300,7 +1300,7 @@ must additionally include the [=interface mixin member|members] of [=interface m
 (identified by the second identifier).
 [=Interface=] |I| is said to <dfn>include</dfn> [=interface mixin=] |M|.
 
-<pre class="webidl" class="syntax">
+<pre highlight="webidl" class="syntax">
     interface_identifier includes mixin_indentifier;
 </pre>
 
@@ -1343,7 +1343,7 @@ No [=extended attributes=] defined in this specification are applicable to [=inc
     <code class="idl">Observable</code>'s [=interface mixin member|members=]
     are always included on objects implementing <code class="idl">Entry</code>.
 
-    <pre class="webidl">
+    <pre highlight="webidl">
         interface Entry {
           readonly attribute unsigned short entryType;
           // ...
@@ -1414,7 +1414,7 @@ you might consider using a [=partial interface=] instead.
 
 For example, instead of:
 
-<pre class="webidl">
+<pre highlight="webidl">
     interface mixin WindowSessionStorage {
       readonly attribute Storage sessionStorage;
     };
@@ -1423,7 +1423,7 @@ For example, instead of:
 
 do:
 
-<pre class="webidl">
+<pre highlight="webidl">
     partial interface Window {
       readonly attribute Storage sessionStorage;
     };
@@ -1436,7 +1436,7 @@ across both window and worker contexts.
 
 For example, instead of the common but verbose:
 
-<pre class="webidl">
+<pre highlight="webidl">
     interface mixin GlobalCrypto {
       readonly attribute Crypto crypto;
     };
@@ -1447,7 +1447,7 @@ For example, instead of the common but verbose:
 
 you can extend the {{WindowOrWorkerGlobalScope}} [=interface mixin=] using a [=partial interface mixin=]:
 
-<pre class="webidl">
+<pre highlight="webidl">
     partial interface mixin WindowOrWorkerGlobalScope {
       readonly attribute Crypto crypto;
     };
@@ -10026,7 +10026,7 @@ that does specify [{{SecureContext}}].
     with one [=operation=] that is executable from all
     contexts, and two which are executable only from secure contexts.
 
-    <pre class="webidl">
+    <pre highlight="webidl">
         [Exposed=Window]
         interface PowerfulFeature {
           // This call will succeed in all contexts.
@@ -10265,7 +10265,7 @@ must not have a [=regular attribute=] or
 
     For example, the following is disallowed:
 
-    <pre class="webidl">
+    <pre highlight="webidl">
         [Exposed=Window]
         interface A1 {
           [Unforgeable] readonly attribute DOMString x;