Apply range definition notation to descriptor and rule's prelude values

Author: cdoublev

css-animations-1/Overview.bs

@@ -224,7 +224,7 @@ Keyframes</h2>
 
 		<dfn>&lt;keyframe-block></dfn> = <<keyframe-selector>># { <<declaration-list>> }
 
-		<dfn>&lt;keyframe-selector></dfn> = from | to | <<percentage>>
+		<dfn>&lt;keyframe-selector></dfn> = from | to | <<percentage [0,100]>>
 	</pre>
 
 	The <<rule-list>> inside of ''@keyframes'' can only contain <<keyframe-block>> rules.

css-fonts-4/Overview.bs

@@ -3161,21 +3161,21 @@ the 'ascent-override', 'descent-override' and 'line-gap-override' descriptors</h
 
 <pre class='descdef'>
 Name: ascent-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,∞]>>
 For: @font-face
 Initial: normal
 </pre>
 
 <pre class='descdef'>
 Name: descent-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,∞]>>
 For: @font-face
 Initial: normal
 </pre>
 
 <pre class='descdef'>
 Name: line-gap-override
-Value: normal | <<percentage>>
+Value: normal | <<percentage [0,∞]>>
 For: @font-face
 Initial: normal
 </pre>

css-syntax-3/Overview.bs

@@ -3271,6 +3271,8 @@ Defining Grammars for Rules and Other Values</h2>
 	assumed to be defined elsewhere.
 	Substituting the <code>&lt;foo></code> for its definition results in a semantically identical grammar.
 
+	For numeric data types, this type notation can annotate any range restrictions using the bracketed range notation described in the <a href="https://www.w3.org/TR/css3-values/#numeric-ranges">Values</a> spec.
+
 	Several types of tokens are written literally, without quotes:
 
 	<ul>