[css-position-4] refer to HTML update the rendering algorithm by correct name (#11225)

Author: cjpearson

css-position-4/Overview.bs

@@ -622,7 +622,7 @@ Top Layer Manipulation {#top-manip}
 		[=set/remove=] |el| from |doc|'s [=Document/top layer=]
 		and [=pending top layer removals=].
 
-	Note: This is intended to be called during the "Update Rendering" step
+	Note: This is intended to be called during the "Update the Rendering" step
 	of HTML's rendering algorithm.
 	It is not intended to be called by other algorithms.