editorial: export more definitions for extension modules (#593)

So that they can be referenced from other specs.

Bug: #506
Bug: #587
Bug: w3c/permissions#425

index.bs

@@ -329,7 +329,7 @@ protocol. These terms are distinct from their representation at the
 
 The protocol is defined using a [[!RFC8610|CDDL]] definition. For the
 convenience of implementors two separate CDDL definitions are defined; the
-<dfn>remote end definition</dfn> which defines the format of messages produced
+<dfn export>remote end definition</dfn> which defines the format of messages produced
 on the [=local end=] and consumed on the [=remote end=], and the <dfn>local end
 definition</dfn> which defines the format of messages produced on the [=remote end=]
 and consumed on the [=local end=]
@@ -1930,7 +1930,7 @@ associated WebDriver [=window handle=] the [=/browsing context id=] must be the
 same as the [=window handle=].
 
 <div algorithm>
-To <dfn>get a browsing context</dfn> given |context id|:
+To <dfn export>get a browsing context</dfn> given |context id|:
 
 1. If |context id| is null, return [=success=] with data null.