[css-overflow-4] Editorial tweaks

Put discussion of overflow:collapse and clamp points before that of
overflow:discard and region breaks. Also, make reference more specific.

Author: frivoal

css-overflow-4/Overview.bs

@@ -707,7 +707,7 @@ Indicating Block-Axis Overflow: the 'block-ellipsis' property</h3>
 	</pre>
 
 	This property allows inserting content into the last line box
-	before a (forced <em>or</em> unforced) <a>region break</a> or a [=clamp point=]
+	before a [=clamp point=] or a (forced <em>or</em> unforced) <a>region break</a>
 	to indicate the continuity of truncated / interrupted content.
 	It only affects line boxes contained directly by the <a>block container</a> itself,
 	but as it inherits, will have an effect on descendants’ line boxes unless overridden.
@@ -718,7 +718,7 @@ Indicating Block-Axis Overflow: the 'block-ellipsis' property</h3>
 	ignoring any intervening [=absolutely positioned=] element
 	or any element closing boundary.
 
-	Note: See [[css-overflow-4#fragmentation]] for a way to generate boxes with such a [=region break=].
+	Note: See ''continue: discard'' for a way to generate boxes with such a [=region break=].
 
 	ISSUE: Should this apply to other types of fragmentation breaks (e.g. pages, columns)?