[css-anchor-position] Add propdef table for anchor() and anchor-size() so they show up in webref. #10764

Author: tabatkins

css-anchor-position-1/Overview.bs

@@ -785,6 +785,11 @@ to refer to the position of one or more [=anchor elements=].
 The ''anchor()'' function resolves to a <<length>>.
 It is only valid to be used in the [=inset properties=].
 
+<pre class="propdef partial">
+Name: top, left, right, bottom, inset-block-start, inset-block-end, inset-inline-start, inset-inline-end
+New values: <<anchor()>>
+</pre>
+
 <pre class=prod>
 	&lt;anchor()> = anchor( <<anchor-element>>? && <<anchor-side>>, <<length-percentage>>? )
 	<dfn><<anchor-element>></dfn> = <<dashed-ident>>
@@ -1311,6 +1316,11 @@ It is only valid to be used in the [=sizing properties=].
 The ''anchor-size()'' Function {#anchor-size-fn}
 ------------------------------
 
+<pre class="propdef partial">
+Name: width, height, inline-size, block-size, min-width, min-height, min-inline-size, min-block-size, max-width, max-height, max-inline-size, max-block-size
+New values:	<<anchor-size()>>
+</pre>
+
 <pre class=prod>
 anchor-size() = anchor-size( [ <<anchor-element>> || <<anchor-size>> ]? , <<length-percentage>>? )
 <dfn><<anchor-size>></dfn> = width | height | block | inline | self-block | self-inline