[css-fonts-5] Use range notation to restrict negative values.

Author: fantasai

css-fonts-5/Overview.bs

@@ -145,7 +145,7 @@ the 'size-adjust' descriptor</h3>
 
 	<pre class='descdef'>
 	Name: size-adjust
-	Value: normal | <<percentage>>
+	Value: normal | <<percentage [0,Infinity]>>
 	For: @font-face
 	Initial: normal
 	</pre>
@@ -182,21 +182,21 @@ the 'ascent-override', 'descent-override', and 'line-gap-override' descriptors</
 
 <pre class='descdef'>
 Name: ascent-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,Infinity]>>
 For: @font-face
 Initial: normal
 </pre>
 
 <pre class='descdef'>
 Name: descent-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,Infinity]>>
 For: @font-face
 Initial: normal
 </pre>
 
 <pre class='descdef'>
 Name: line-gap-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,Infinity]>>
 For: @font-face
 Initial: normal
 </pre>
@@ -213,7 +213,7 @@ which results in different text layouts.
 
 For the 'ascent-override', 'descent-override' and 'line-gap-override' descriptors, when the
 descriptor value is a percentage, the corresponding metric value is resolved as the
-given percentage multiplied by the used font size. Negative values are invalid at parse time.
+given percentage multiplied by the used font size.
 
 None of these descriptors affect the calculation of
 <a href="https://drafts.csswg.org/css-values-4/#font-relative-lengths">Font-relative Lengths</a>.
@@ -302,14 +302,14 @@ Issue(5518):
 
     <pre class='descdef'>
         Name: superscript-size-override
-        Value: normal | <<percentage>>
+        Value: normal | <<percentage [0,Infinity]>>
         For: @font-face
         Initial: normal
     </pre>
 
     <pre class='descdef'>
         Name: subscript-size-override
-        Value: normal | <<percentage>>
+        Value: normal | <<percentage [0,Infinity]>>
         For: @font-face
         Initial: normal
     </pre>