[css-text] Include more inseparable characters

Author: fantasai

css-text/Overview.html

@@ -1293,8 +1293,12 @@ <h3 id=line-break><span class=secno>5.2. </span> Breaking Rules for
       々 U+3005, 〻 U+303B, ゝ U+309D, ゞ U+309E, ヽ U+30FD,
       ヾ U+30FE
 
-     <li>breaks between some inseparable characters:<br>
-      ‥ U+2025, … U+2026
+     <li>breaks between inseparable characters such as ‥ U+2025,
+      … U+2026 i.e. characters with the Unicode Line Break property
+      <code>IN</code>. (See <a
+      href="http://www.unicode.org/Public/UNIDATA/LineBreak.txt">LineBreak.txt</a>
+      in <a href="#UNICODE"
+      rel=biblioentry>[UNICODE]<!--{{!UNICODE}}--></a>.)
     </ul>
     If the <a href="#content-language"><i>content language</i></a> is
     Chinese, Japanese, or Korean, then additionally:

css-text/Overview.src.html

@@ -914,8 +914,10 @@ <h3 id="line-break">
           <li>breaks before iteration marks:<br>
             &#x3005;&nbsp;U+3005,  &#x303B;&nbsp;U+303B,  &#x309D;&nbsp;U+309D,
             &#x309E;&nbsp;U+309E,  &#x30FD;&nbsp;U+30FD,  &#x30FE;&nbsp;U+30FE
-          <li>breaks between some inseparable characters:<br>
-            &#x2025;&nbsp;U+2025,  &#x2026;&nbsp;U+2026
+          <li>breaks between inseparable characters
+            such as &#x2025;&nbsp;U+2025,  &#x2026;&nbsp;U+2026
+            i.e. characters with the Unicode Line Break property <code>IN</code>.
+            (See <a href="http://www.unicode.org/Public/UNIDATA/LineBreak.txt">LineBreak.txt</a> in [[!UNICODE]].)
         </ul>
         If the <i>content language</i> is Chinese, Japanese, or Korean, then additionally:
         <ul>