[css-text-decor-3] Remove commented-out section that's been ported to L4.

Author: fantasai

css-text-decor-3/Overview.bs

@@ -531,104 +531,6 @@ Text Underline Position: the 'text-underline-position' property</h3>
 		-->
 	</div>
 
-<!--
-<h3 id="line-position">
-Determining the Position and Thickness of Line Decorations</h3>
-
-	Since line decorations can span elements with varying font sizes and
-	vertical alignments, the best position for a line decoration is not
-	necessarily the ideal position dictated by the <i>decorating box</i>.
-	Instead, it's calculated, per line, from all text decorated by the <i>decorating box</i> on that line,
-	the <dfn>considered text</dfn>.
-	However, descendants of the <i>decorating box</i>
-	that are skipped due to 'text-decoration-skip',
-	descendant inlines with ''text-decoration-skip: ink'',
-	and any descendants that do not participate in the <i>decorating box</i>’s inline formatting context
-	are excluded from the set of <i>considered text</i>.
-
-
-	The line decoration positions are then calculated
-	per line
-	as follows
-	(treating <a href="#underline-left"><i>over</i>-positioned underlines</a> as <i>over</i> lines
-	and <a href="#underline-left"><i>under</i>-positioned overlines</a> as <i>under</i> lines):
-
-	<dl>
-		<dt><a href="https://www.w3.org/TR/css-writing-modes/#over"><i>over</i></a> lines
-		<dd>
-		  Align the line decoration with respect to the highest
-		  <a href="https://www.w3.org/TR/css-writing-modes/#over"><i>over</i></a> EM-box edge
-		  of the <i>considered text</i>.
-
-		<dt><a href="#underline-alphabetic"><i>alphabetic</i></a> underlines
-		<dd>
-		  The alphabetic underline position is calculated by taking
-		  the ideal offset (from the alphabetic baseline) of each run of <i>considered text</i>,
-		  averaging those, and then using the lowest alphabetic baseline to actually position the line.
-		  (Alphabetic baselines can differ between ''baseline''-aligned boxes
-		   if the dominant baseline is non-alphabetic.)
-		  To prevent superscripts and subscripts from throwing this position off-kilter,
-		  an inline with a non-initial computed 'vertical-align'
-		  is treated as having the ideal underline position of its parent.
-
-		<dt>non-alphabetic <a href="https://www.w3.org/TR/css-writing-modes/#under"><i>under</i></a> lines
-		<dd>
-		  Position the line decoration with respect to the lowest
-		  <a href="https://www.w3.org/TR/css-writing-modes/#under"><i>under</i></a> EM-box edge
-		  of the <i>considered text</i>.
-
-		<dt>line-throughs
-		<dd>
-		  Line-throughs essentially use the same sort of averaging as for alphabetic underlines,
-		  but recompute the position when drawing across a descendant with a different computed 'font-size'.
-		  (This ensures that the text remains effectively “crossed out” despite any font size changes.)
-		  For each run of <i>considered text</i> with the same 'font-size',
-		  compute an ideal position averaged from its font metrics.
-		  To prevent superscripts and subscripts from throwing this position off-kilter,
-		  an inline with a non-initial computed 'vertical-align'
-		  is treated as having the ideal underline position of its parent.
-		  Position the portion of the line across each decorated fragment at that position.
-
-		  <p class='issue'>
-		    For simplicity, line-throughs should draw over each element at that element's preferred/averaged position.
-		    This can produce some undesirable jumpiness,
-		    but there doesn't appear to be any way to avoid that which is correct in all instances,
-		    and all attempts are worryingly complex.
-		    What position should line-throughts adopt over elements that have a different font-size,
-		    but no <i>considered text</i>?
-	</dl>
-
-
-	CSS does not define the thickness of line decorations.
-	In determining the thickness of text decoration lines,
-	user agents may consider the font sizes, faces, and weights of descendants
-	to provide an appropriately averaged thickness.
-
-	<div class="example">
-		The following figure shows the averaging for underline:
-
-		<img alt="In the first rendering of the underlined text '1st a'
-		          with 'st' as a superscript, both the '1st' and the 'a'
-		          are rendered in a small font. In the second rendering,
-		          the 'a' is rendered in a larger font. In the third, both
-		          '1st' and 'a' are large."
-		     height="105" src="images/underline-averaging.gif" width="326">
-
-		In the three fragments of underlined text, the underline is drawn
-		consecutively lower and thicker as the ratio of large text to small
-		text increases.
-
-		Using the same example, a line-through would in the second fragment,
-		instead of averaging the two font sizes,
-		split the line-through into two segments:
-
-		<img alt="" src="images/linethrough-averaging.gif">
-
-		In both cases, however, the superscript, due to the vertical-alignment shift,
-		has no effect on the position of the line.
-	</div>
--->
-
 	Some font formats (such as OpenType) can offer information
 	about the appropriate position of a line decoration.
 	The UA should use such information