[css-ruby] Improve cross-section linking

Author: frivoal

css-ruby-1/Overview.bs

@@ -600,7 +600,8 @@ Autohiding Base-identical Annotations</h3>
 <h3 id="white-space">
 White Space Collapsing</h3>
 
-	White space within a ruby structure is <a href="#anon-gen-discard-space">discarded</a>
+	As discussed in [[#box-fixup]],
+	white space within a ruby structure is <a href="#anon-gen-discard-space">discarded</a>:
 	<ul>
 		<li>at the beginning and end of a [=ruby container=], [=annotation container=], or [=base container=],
 		<li>between a [=base container=] and its following [=annotation container=],
@@ -623,7 +624,7 @@ White Space Collapsing</h3>
 	as [=inter-base white space|inter-base=],
 	[=inter-annotation white space|inter-annotation=],
 	or [=inter-segment white space=].
-	(See <a href="#box-fixup">Anonymous Ruby Box Generation</a>, above.)
+	(See <a href="#anon-gen-interpret-space">Interpret intra-level white space</a>, above.)
 
 	<div class="example">
 		The rules preserving white space allow ruby to be used with space-separated scripts such as Latin.