[css-values-4] Clarify in the prose that min/max/round also need all their calcs to be the same type. w3c#7496

Author: tabatkins

css-values-4/Overview.bs

@@ -2888,6 +2888,12 @@ Comparison Functions: ''min()'', ''max()'', and ''clamp()''</h3>
 	(That is, given ''clamp(MIN, VAL, MAX)'',
 	it represents exactly the same value as ''max(MIN, min(VAL, MAX))'').
 
+	For all three functions,
+	the argument [=calculations=] can resolve to any <<number>>, <<dimension>>, or <<percentage>>,
+	but must have the <em>same</em> [=determine the type of a calculation|type=],
+	or else the function is invalid;
+	the result will have the same [=CSSNumericValue/type=] as the arguments.
+
 	<div class="example">
 
 		''min()'', ''max()'', and ''clamp()'' can be used to make sure a value doesn't exceed a "safe" limit:
@@ -3916,7 +3922,8 @@ Type Checking</h3>
 
 	* The [=CSSNumericValue/type=] of a ''calc()'' or ''abs()'' expression
 		is the [=CSSNumericValue/type=] of its contained [=calculation=].
-	* The [=CSSNumericValue/type=] of a ''min()'', ''max()'', or ''clamp()'' expression
+	* The [=CSSNumericValue/type=] of a
+		''min()'', ''max()'', ''clamp()'', ''hypot()'', ''round()'', ''mod()'', or ''rem()'' expression
 		is the result of [=add two types|adding the types=]
 		of its comma-separated [=calculations=].
 	* The [=CSSNumericValue/type=] of a ''sign()'' expression
@@ -3927,9 +3934,6 @@ Type Checking</h3>
 		is «[ "angle" → 1 ]».
 	* The [=CSSNumericValue/type=] of a ''pow()'', ''sqrt()'', ''log()'', or ''exp()'' expression
 		is «[ "number" → 1 ]».
-	* The [=CSSNumericValue/type=] of a ''hypot()'', ''round()'', ''mod()'', or ''rem()'' expression
-		is the result of [=add two types|adding the types=]
-		of its comma-separated [=calculations=].
 
 	For each of the above,
 	if the [=CSSNumericValue/type=] is failure,