[selectors-4][editorial] Don't use 'should' in a Note.

Author: tabatkins

selectors-4/Overview.bs

@@ -2397,11 +2397,11 @@ The Focus-Indicated Pseudo-class: '':focus-visible''</h3>
 			don't [=indicate focus=].
 		* If the previously-focused element [=indicated focus=],
 			and a script causes focus to move elsewhere,
-			the newly focused element should [=indicate focus=].
+			[=indicate focus=] on the newly focused element.
 
 			Conversely, if the previously-focused element did not [=indicate focus=],
 			and a script causes focus to move elsewhere,
-			the newly focused element should also not [=indicate focus=].
+			don't [=indicate focus=] on the newly focused element.
 	</div>
 
 	User agents should also use '':focus-visible'' to specify the default focus style,