[css-view-transitions-2] Require one or more custom ident for view-transition-class and type (w3c#9896)

* [css-view-transitions-2] Require one or more custom ident for view-transition-class

* [css-view-transitions-2] Require one or more custom ident for @view-transition type

Author: cdoublev

css-view-transitions-2/Overview.bs

@@ -259,7 +259,7 @@ for multiple view transition pseudo elements without having to replicate the cor
 
 	<pre class=propdef>
 	Name: view-transition-class
-	Value: none | <<custom-ident>>*
+	Value: none | <<custom-ident>>+
 	Initial: none
 	Inherited: no
 	Percentages: n/a
@@ -279,7 +279,7 @@ for multiple view transition pseudo elements without having to replicate the cor
 		: <dfn>none</dfn>
 		:: No class would apply to the [=named view transition pseudo-elements=] generated for this element.
 
-		: <dfn><<custom-ident>>*</dfn>
+		: <dfn><<custom-ident>>+</dfn>
 		:: All of the specified <<custom-ident>> values (apart from <css>none</css>) are applied when used in [=named view transition pseudo-element=] selectors.
 			<css>none</css> is an invalid <<custom-ident>> for 'view-transition-class', even when combined with other <<custom-ident>>s.
 
@@ -440,7 +440,7 @@ Note: as per default behavior, the ''@view-transition'' rule can be nested insid
 	<pre class='descdef'>
 	Name: type
 	For: @view-transition
-	Value: none | <<custom-ident>>*
+	Value: none | <<custom-ident>>+
 	Initial: none
 	</pre>