[css-navigation-1] Miscellaneous updates to css-navigation draft.

(This is part of importing the history from WICG/declarative-partial-updates.)

Author: dbaron

css-navigation-1/Overview.bs

@@ -179,6 +179,13 @@ as follows:
 			[=URL pattern/match|matches=]
 			the [=route location URL pattern=] of <<route-location>>.
 
+		TODO: Update this definition to handle redirects better.
+		In particular, we'd like the ''to:'' URL to change
+		at only a single time,
+		from the original URL of the navigation to the final one.
+		There is already a well-defined definition and processing model
+		that we can depend on.
+
 	ISSUE: The above definitions of from and to apparently don't work right
 	if you start a same-document navigation (e.g., with {{History/pushState}})
 	in the middle of a cross-document navigation.
@@ -244,6 +251,10 @@ ISSUE: This should probably have a more formal definition of the function,
 but I can't find the formal definitions of the existing ''if()'' functions
 to model it after.
 
+<h2 id="link-route-pseudo-classes">Pseudo-classes for route-related links</h2>
+
+TODO: To be written.
+
 <h2 id="urlpattern-function">The ''urlpattern()'' function</h2>
 
 <!--
@@ -255,7 +266,7 @@ exported any more, since it was exported for this definition.
 
 -->
 
-The <dfn function>urlpattern()</dfn> function represents a [=URL pattern=],
+The <dfn export function>urlpattern()</dfn> function represents a [=URL pattern=],
 which can be used to match URLs.
 
 <pre class="prod def">
@@ -296,3 +307,11 @@ using the steps of the <dfn>create a URL pattern for urlpattern()</dfn> algorith
 NOTE:  This function requires that its argument is quoted.
 This differs from the ''url()'' function,
 which allows its argument to be quoted or unquoted.
+
+To <dfn export>serialize a ''urlpattern()'' function</dfn> <var>f</var>,
+[=serialize a function=] <var>f</var>,
+using [=serialize a string=] on the single argument
+to serialize <var>f</var>'s contents.
+
+NOTE: This is defined this way because {{URLPattern}}
+intentionally does not provide a serialization.