[css-text-3] Clarify notes about scope of line-break rules. #1252

Author: fantasai

css-text-3/Overview.bs

@@ -1240,16 +1240,20 @@ Line Breaking Details</h3>
         </ul>
     </ul>
 
-    <p class="note">Note: In the requirements listed above,
-      no distinction is made among the levels of strictness in non-CJK text:
-      only CJK codepoints are affected,
-      unless the text is marked as <a for=writing-system>Chinese</a> or <a for=writing-system>Japanese</a>,
-      in which case some additional common codepoints are affected.
+    <p class="note">Note:
+      The specific rules listed above
+      only create distinctions in CJK text:
+      unless the writing system is tagged as
+      <a for=writing-system>Chinese</a> or <a for=writing-system>Japanese</a>,
+      only CJK codepoints are affected.
+      Future levels may add additional specific rules
+      for other writing systems and languages
+      as their requirements become known.
 
     <div class="example">
       As UAs can add additional distinctions
       between ''line-break/strict''/''line-break/normal''/''line-break/loose'' modes,
-      these values can exhibit other differences as well.
+      these values can exhibit differences in other writing systems as well.
       For example, a UA with sufficiently-advanced Thai language processing ability
       could choose to map different levels of strictness in Thai line-breaking
       to these keywords,