[css-inline-3] Add some cross-links in A+D section. Adjust to handle dominant baseline that don't line up with zero coord.

Author: fantasai

css-inline-3/Overview.bs

@@ -785,17 +785,17 @@ Line Spacing: the 'line-height' property</h3>
 	Note that these are metrics of the font as a whole
 	and need not correspond to the ascender and descender of any individual glyph.
 
-	The User Agent must align the glyphs in a non-replaced inline box
-	to each other by their relevant baselines.
+	The User Agent must align the glyphs in a non-replaced [=inline box=]
+	to each other by their [=dominant baselines=].
 	Then, for each glyph,
 	determine the <var>A</var> and <var>D</var>.
-	Note that glyphs in a single element
-	may come from different fonts
-	and thus need not all have the same <var>A</var> and <var>D</var>.
+	(Note that glyphs in a single element
+	can come from different fonts
+	and thus need not all have the same <var>A</var> and <var>D</var>.)
 	If the inline box contains no glyphs at all,
 	or if it contains only glyphs from fallback fonts,
 	it is considered to contain a “strut” (an invisible glyph of zero width)
-	with the <var>A</var> and <var>D</var> of the element's first available font.
+	with the <var>A</var> and <var>D</var> of the box's [=first available font=].
 
 	<p id="inline-box-height">When the value of the 'line-height' property
 	is something other than ''line-height/normal'',
@@ -843,11 +843,14 @@ Line Spacing: the 'line-height' property</h3>
 	implementations that use OpenType or TrueType fonts
 	use the metrics <code>sTypoAscender</code> and <code>sTypoDescender</code>
 	from the font's OS/2 table
-	for <var>A</var> and <var>D</var>
-	(after scaling to the current element's font size).
+	(after scaling to the current element's font size)
+	to find <var>A</var> and <var>D</var>.
 	In the absence of these metrics,
 	the "Ascent" and "Descent" metrics from the HHEA table should be used.
 
+	Note: The ascent and descent metrics in the font data might need to be adjusted
+	to account for the [=dominant baseline=]’s offset from zero.
+
 <h3 id="line-sizing-property">
 Line Sizing Containment: the 'line-sizing' property</h3>