[css-break-3] Apply clarification requested in #1823, widows/orphans apply to block containers that directly contain line boxes (only)

Author: fantasai

css-break-3/Overview.bs

@@ -434,7 +434,7 @@ Breaks Between Lines: 'orphans', 'widows'</h3>
   Name: orphans, widows
   Value: <<integer>>
   Initial: 2
-  Applies to: block containers
+  Applies to: <a>block containers</a> that establish an <a>inline formatting context</a>
   Inherited: yes
   </pre>