[css-values-3][css-values-4] Clarify that specs can override the default out-of-range numbers are invalid handling. Fixes #3270

Author: fantasai

css-values-3/Overview.bs

@@ -667,6 +667,7 @@ Numeric Data Types</h2>
 
 		Properties may restrict numeric values to some range.
 		If the value is outside the allowed range,
+		unless otherwise specified,
 		the declaration is invalid and must be <a href="https://www.w3.org/TR/CSS21/conform.html#ignore">ignored</a>.
 
 		CSS theoretically supports infinite precision and infinite ranges for all value types;
@@ -2159,6 +2160,15 @@ Changes</h2>
 		<li>Defined <<'property'>> syntax to refer to the property without any top-level #-multiplier,
 			to make the notation usable with common list-valued property patterns.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/3146">Issue 3146</a>)
+		<li>Clarified that numeric values outside the allowed range
+			are not ignored if a more specific spec defines other handling.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/3270">Issue 3270</a>)
+			<blockquote>
+				Properties may restrict numeric values to some range.
+				If the value is outside the allowed range,
+				<ins>unless otherwise specified,</ins>
+				the declaration is invalid and must be <a href="https://www.w3.org/TR/CSS21/conform.html#ignore">ignored</a>.
+			</blockquote>
 	</ul>
 
 	Changes since the <a href="https://www.w3.org/TR/2016/CR-css-values-3-20160929/">29 September 2016 Candidate Recommendation</a> are:

css-values-4/Overview.bs

@@ -784,6 +784,7 @@ Numeric Data Types</h2>
 
 		Properties may restrict numeric values to some range.
 		If the value is outside the allowed range,
+		unless otherwise specified,
 		the declaration is invalid and must be <a href="https://www.w3.org/TR/CSS21/conform.html#ignore">ignored</a>.
 
 		CSS theoretically supports infinite precision and infinite ranges for all value types;