[css-text-3] Generically clarify that we ignore inline box boundaries and out-of-flow elements when determining text adjacency. #4259

Author: fantasai

css-text-3/Overview.bs

@@ -366,6 +366,13 @@ Text Processing</h3>
     text-encoding/shaping-tatweel-003.html
   </wpt>
 
+  For the purpose of determining adjacency for text processing
+  (such as white space processing, text transformation, line-breaking, etc.),
+  and thus in general within this specification,
+  intervening [=inline box=] boundaries and [=out-of-flow=] elements
+  must be ignored.
+  With respect to text shaping, however, see [[#boundary-shaping]].
+
 <h2 id="transforming">
   Transforming Text</h2>
 
@@ -1550,7 +1557,6 @@ Text Processing</h3>
     <p>As each line is laid out,</p>
     <ol>
       <li>A sequence of [=collapsible=] [=spaces=] at the beginning of a line
-        (ignoring any intervening <a>inline box</a> boundaries)
         is removed.
 
         <wpt>
@@ -1593,7 +1599,6 @@ Text Processing</h3>
         Note: See [[UAX9]] for <a href="http://unicode.org/reports/tr9/#L1">rules on how U+0009 tabulation interacts with bidi</a>.
 
       <li>A sequence at the end of a line
-        (ignoring any intervening <a>inline box</a> boundaries)
         of <a>collapsible</a> [=spaces=]
         and/or [=other space separators=] whose 'white-space' value collapses spaces
         is removed.