[css-text] Reduce ambiguity in spec text

Follow up on #8972

Author: w3cgruntbot

css-text-3/Overview.bs

@@ -3379,7 +3379,9 @@ Line Breaking Details</h3>
 			including U+00A0 NO-BREAK SPACE.
 			However,
 			with the exception of U+00A0 NO-BREAK SPACE,
-			non-tailorable Unicode line breaking rules must be honored.
+			there must be no [=soft wrap opportunity=]
+			between [=atomic inlines=] and adjacent characters
+			belonging to the Unicode GL, WJ, or ZWJ line breaking classes.
 			[[UAX14]]
 
 			<wpt>
@@ -8283,7 +8285,9 @@ Recent Changes</h3>
 			<ins>
 			However,
 			with the exception of U+00A0 NO-BREAK SPACE,
-			non-tailorable Unicode line breaking rules must be honored.
+			there must be no [=soft wrap opportunity=]
+			between [=atomic inlines=] and adjacent characters
+			belonging to the Unicode GL, WJ, or ZWJ line breaking classes.
 			[[UAX14]]
 			</ins>
 		</blockquote>

css-text-4/Overview.bs

@@ -4238,7 +4238,9 @@ Line Breaking Details</h3>
 			including U+00A0 NO-BREAK SPACE.
 			However,
 			with the exception of U+00A0 NO-BREAK SPACE,
-			non-tailorable Unicode line breaking rules must be honored.
+			there must be no [=soft wrap opportunity=]
+			between [=atomic inlines=] and adjacent characters
+			belonging to the Unicode GL, WJ, or ZWJ line breaking classes.
 			[UAX14]
 
 			<wpt>