[css-text] Add EAW=A to block scripts if the content language is CJK

Author: kojiishi

css-text/Overview.bs

@@ -2588,7 +2588,8 @@ Appendix C: Scripts and Spacing</h2>
   	<dt><dfn>block scripts</dfn></dt>
   	<dd>CJK and by extension all Wide characters (see [[!UAX11]].)
   	  The following scripts are included: Bopomofo, Han, Hangul, Hiragana, Katakana, and Yi.
-  	  Characters of the East Asian Width property [[!UAX11]] W and F are also included.
+  	  Characters of the East Asian Width property [[!UAX11]] W and F are also included,
+  	  but A are included only if the <i>content language</i> is Chinese, Korean, or Japanese.
   	<dt><dfn>clustered scripts</dfn></dt>
   	<dd>Scripts that have discrete units,
       break only at word boundaries,