[css-anchor-position][editorial] Replace the struck-out text with new intro, now that we've settled on the design.

Author: tabatkins

css-anchor-position-1/Overview.bs

@@ -983,14 +983,21 @@ so positioning an element in any particular fashion
 might result in the positioned element overflowing its [=containing block=]
 or being positioned partially off screen.
 
-<s>To ameliorate this, an [=absolutely positioned=] element
-can use the 'position-fallback' property
-to refer to a ''@position-fallback'' block,
-giving a list of possible style rules to try out.
+To ameliorate this, an [=absolutely positioned=] element
+can use the 'position-try-options' property
+to refer to several variant sets of positioning/alignment properties
+(generated from the element's existing styles,
+or specified in ''@position-try'' rules)
+that the UA can try if the element overflows its initial position.
 Each is applied to the element, one by one,
 and the first that doesn't cause the element
 to overflow its [=containing block=]
-is taken as the winner.</s>
+is taken as the winner.
+
+'position-try-order' allows these options
+to additional be sorted by the available space they define,
+if it's more important for the element to have as much space as possible
+rather than strictly follow some declared order.
 
 Giving Fallback Options: the 'position-try-options' property {#position-try-options}
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