[css-text-3] Cross-reference to where bidi line breaking interactions are defined. #5121

Author: fantasai

css-text-3/Overview.bs

@@ -2410,13 +2410,22 @@ Text Processing</h3>
 Line Breaking Details</h3>
 
   <p>When determining <a>line breaks</a>:
+
   <ul>
+    <li>The interaction of [=line breaking=] and bidirectional text is defined by
+      [[!CSS-WRITING-MODES-3]] and [[!UAX9]],
+      see in particular [[css-writing-modes-3#bidi-algo]]
+      and <a href="http://unicode.org/reports/tr9/#Reordering_Resolved_Levels">UAX9&sect;3.4 Reordering Resolved Levels</a>.
+
     <li>Regardless of the 'white-space' value,
       lines always break at each <a>preserved</a> forced break character:
       thus
       for all values, line-breaking behavior defined for
       the <code>BK</code> and <code>NL</code> Unicode line breaking classes [[!UAX14]]
       must be honored.
+
+      Note: The bidi implications of such [=forced line breaks=] are defined by [[!UAX9]].
+
     <li>Except where explicitly defined otherwise
       (e.g. for ''line-break: anywhere'' or ''overflow-wrap: anywhere'')
       line breaking behavior defined for