[css-text-4] Add Unicode Category for nonspacing marks

Author: xfq

css-text-4/Overview.bs

@@ -5580,8 +5580,8 @@ Hyphenation Character Limits: the 'hyphenate-limit-chars' property</h4>
 	If the word does not meet the required minimum number of characters
 	in the word / before the hyphen / after the hyphen,
 	then the word must not be hyphenated.
-	Nonspacing combining marks (<span class="issue">Unicode class</span>)
-	and intra-word punctuation (Unicode classes P*)
+	Nonspacing combining marks (Unicode General Category Mn)
+	and intra-word punctuation (Unicode General Category P*)
 	do not count towards the minimum.
 
 	If three values are specified,