[css-text-4] Add text-spacing-trim: trim-all

See #8482

Author: frivoal

css-text-4/Overview.bs

@@ -10379,7 +10379,7 @@ CJK Punctuation Spacing: the 'text-spacing-trim' property</h3>
 	Values are defined as follows:
 
 	<pre class=prod>
-		<dfn><<spacing-trim>></dfn> = space-all |  trim-auto | [ allow-end || space-first ]
+		<dfn><<spacing-trim>></dfn> = space-all | trim-auto | [ allow-end || space-first ] | trim-all
 	</pre>
 
 	<dl dfn-for=text-spacing-trim dfn-type=value>
@@ -10447,6 +10447,15 @@ CJK Punctuation Spacing: the 'text-spacing-trim' property</h3>
 			Otherwise as ''trim-auto''
 			(unless ''space-first'' is also specified).
 
+		<dt><dfn>trim-all</dfn>
+		<dd>
+			Set <a>fullwidth opening punctuation</a>,
+			<a>fullwidth closing punctuation</a>,
+			and <a>fullwidth middle dot punctuation</a>
+			with half-width glyphs,
+			without regards for the position within the line
+			nor for adjacent characters.
+
 		<dt><dfn>auto</dfn>
 		<dd>
 			The user agent chooses a set of typographically high quality spacing values.
@@ -10510,7 +10519,10 @@ Fullwidth Punctuation Collapsing</h4>
 	the font has proportional ideographs
 	and the fullwidth advance width cannot be reliably determined by measuring glyphs.
 
-	Unless 'text-spacing-trim' is set to ''space-all''
+	If 'text-spacing-trim' is ''trim-all'',
+	the UA must collapse the space typically associated with such full width glyphs
+	regardless of the context in which they appear.
+	Otherwise, unless 'text-spacing-trim' is set to ''space-all''
 	(or the font has proportional fullwidth punctuation glyphs),
 	the UA must collapse the space typically associated with such full width glyphs
 	when placed adjacently on a line
@@ -12837,6 +12849,8 @@ Changes</h2>
 		(since it can no longer depend on <code>word-boundary-detection</code>).
 		and update supporting related mechanics.
 	* Rename <code>word-boundary-expansion</code> to 'word-space-transform'
+	* Add ''trim-all'' to 'text-spacing-trim'.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/8482">Issue 8482</a>)
 
 	Significant changes since the <a href="https://www.w3.org/TR/2023/WD-css-text-4-20230301/">1 March 2022 Working Draft</a> include:
 	* Completed the translation of 'white-space' to multiple longhands by