[css-writing-modes-3] Undefine processing of spaces inside text-combine-upright for L3

See w3c#4139

Author: frivoal

css-writing-modes-3/Overview.bs

@@ -2400,9 +2400,8 @@ Layout Rules</h4>
     but using the specified font settings),
     similar to the contents of an ''inline-block'' box
     with a [=horizontal writing mode=] and a 'line-height' of ''1em''.
-    Any [=document white space=] included at the start/end of the combined text
-    <em>is</em> [[css-text-3#white-space-processing|processed]] [[!CSS-TEXT-3]]
-    as at the start/end of such an inline block.
+    Processing of [=document white space=] included in the combined text
+    is not defined in this level.
     The effective size of the composition is assumed to be 1em square;
     anything outside the square is not measured for layout purposes.
     The UA should center the glyphs horizontally and vertically within the measured 1em square.
@@ -2497,10 +2496,9 @@ Privacy and Security Considerations {#priv-sec}
         but not its computed value.
         Also, optionally allow propagating 'text-orientation' as well.
         (<a href="https://github.com/w3c/csswg-drafts/issues/3066">Issue 3066</a>)
-    <li>Clarified that white space within--
-        particularly at the start/end of--
-        a 'text-combine-upright' combined text sequence
-        is processed the same way as in an inline block.
+    <li>Make the processing of white space
+        in a 'text-combine-upright' combined text sequence
+        explicitely undefined in this level
         (<a href="https://github.com/w3c/csswg-drafts/issues/4139">Issue 4139</a>)
         <blockquote>
           <p>When combining text as for ''text-combine-upright: all'',
@@ -2510,9 +2508,8 @@ Privacy and Security Considerations {#priv-sec}
           but using the specified font settings),
           similar to the contents of an ''inline-block'' box
           with a [=horizontal writing mode=] and a 'line-height' of ''1em''.
-          <ins>Any [=document white space=] included at the start/end of the combined text
-          <em>is</em> [[css-text-3#white-space-processing|processed]] [[!CSS-TEXT-3]]
-          as at the start/end of such an inline block.</ins>
+          <ins>Processing of [=document white space=] included in the combined text
+          is not defined in this level.</ins>
         </blockquote>
   </ul>