[css-text] Clarify interaction between conditionally and unconditionally hanging

See #9724

Author: frivoal

css-text-3/Overview.bs

@@ -7117,6 +7117,13 @@ Hanging Glyphs</h3>
 	white-space/white-space-intrinsic-size-017.html
 	</wpt>
 
+	When conditionally hangable glyphs at the end of the line
+	are immediately preceded by (unconditionally) hangable glyphs,
+	the unconditionally hangable glyphs hang
+	if and only if all subsequent conditionally hangable glyphs do indeed hang;
+	otherwise, the (unconditionally) hangable glyphs are effectively not at the end of the line
+	and do not hang.
+
 	Non-zero inline-axis borders or padding between
 	a [=hang=]able glyph and the edge of the line prevent the glyph from hanging.
 	For example, a period at the end of an inline box with end padding
@@ -8435,6 +8442,9 @@ Recent Changes</h3>
 		rather than mentioning ''vertical-align/baseline'' specifically,
 		to avoid confusion given further developments to 'vertical-align'.
 		(<a href="https://github.com/w3c/csswg-drafts/issues/13277">Issue 13277</a>)
+	* Clarified the interaction between conditionally and unconditionally hangable glyphs
+		at the end of a line.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/9724">Issue 9724</a>)
 
 	The following changes have been made since
 	the <a href="https://www.w3.org/TR/2024/CRD-css-text-3-20240930/">September 2024 Candidate Recommendation Draft</a>:

css-text-4/Overview.bs

@@ -11866,6 +11866,13 @@ Hanging Glyphs</h3>
 	white-space/white-space-intrinsic-size-017.html
 	</wpt>
 
+	When conditionally hangable glyphs at the end of the line
+	are immediately preceded by (unconditionally) hangable glyphs,
+	the unconditionally hangable glyphs hang
+	if and only if all subsequent conditionally hangable glyphs do indeed hang;
+	otherwise, the (unconditionally) hangable glyphs are effectively not at the end of the line
+	and do not hang.
+
 	Non-zero inline-axis borders or padding between
 	a [=hang=]able glyph and the edge of the line prevent the glyph from hanging.
 	For example, a period at the end of an inline box with end padding