[css-counter-styles-3][editorial] Just use 'defined', not 'currently-…

…defined', to avoid any implication of temporality. Fixes #4205.

css-counter-styles-3/Overview.bs

@@ -695,7 +695,7 @@ Building from Existing Counter Styles: the ''extends'' system
 	it must not contain a 'symbols' or 'additive-symbols' descriptor,
 	or else the ''@counter-style'' rule is invalid.
 
-	If the specified counter style name isn't the name of any currently-defined counter style,
+	If the specified counter style name isn't the name of any defined counter style,
 	it must be treated as if it was extending the ''decimal'' counter style.
 	If one or more ''@counter-style'' rules form a cycle with their ''extends'' values,
 	all of the counter styles participating in the cycle
@@ -992,7 +992,7 @@ Defining fallback: the 'fallback' descriptor</h3>
 	value, etc.).
 
 	If the value of the 'fallback' descriptor isn't the name of any
-	currently-defined counter style, the used value of the 'fallback' descriptor
+	defined counter style, the used value of the 'fallback' descriptor
 	is ''decimal'' instead.  Similarly, while following fallbacks to find
 	a counter style that can render the given counter value, if a loop in the
 	specified fallbacks is detected, the ''decimal'' style must be used instead.