[css-values-4] Consistently use math-minus for negative zero, too.

Author: tabatkins

css-values-4/Overview.bs

@@ -3114,7 +3114,7 @@ Type Checking</h3>
 	and between nested calculations:
 
 	* Negative zero
-		(0<sup>-</sup>)
+		(0<sup>−</sup>)
 		can be produced literally by negating a zero
 		(''-0''),
 		or by a multiplication or division that produces zero
@@ -3131,41 +3131,41 @@ Type Checking</h3>
 		they're "censored" away into an "unsigned" zero.
 	* ''-0 + -0''
 		or ''-0 - 0''
-		produces 0<sup>-</sup>.
+		produces 0<sup>−</sup>.
 		All other additions or subtractions that would produce a zero
 		produce 0<sup>+</sup>.
-	* Multiplying or dividing 0<sup>-</sup> with a positive number
+	* Multiplying or dividing 0<sup>−</sup> with a positive number
 		(including 0<sup>+</sup>)
 		produces a negative result
-		(either 0<sup>-</sup> or −∞),
-		while multiplying or dividing 0<sup>-</sup> with a negative number
+		(either 0<sup>−</sup> or −∞),
+		while multiplying or dividing 0<sup>−</sup> with a negative number
 		produces a positive result.
 
 		(In other words,
-		multiplying or dividing with 0<sup>-</sup>
+		multiplying or dividing with 0<sup>−</sup>
 		follows standard sign rules.)
-	* When comparing 0<sup>+</sup> and 0<sup>-</sup>,
-		0<sup>-</sup> is less than 0<sup>+</sup>.
-		For example, ''min(0, -0)'' must produce 0<sup>-</sup>,
+	* When comparing 0<sup>+</sup> and 0<sup>−</sup>,
+		0<sup>−</sup> is less than 0<sup>+</sup>.
+		For example, ''min(0, -0)'' must produce 0<sup>−</sup>,
 		''max(0, -0)'' must produce 0<sup>+</sup>,
 		and ''clamp(0, -0, 1)'' must produce 0<sup>+</sup>.
 
 	If a <dfn export>top-level calculation</dfn>
 	(a [=math function=] not nested inside of another [=math function=])
 	would produce a NaN,
 	it instead produces +∞.
-	If a [=top-level calculation=] would produce 0<sup>-</sup>,
+	If a [=top-level calculation=] would produce 0<sup>−</sup>,
 	it instead produces the standard "unsigned" zero.
 
 	<div class=example>
 		For example, ''calc(-5 * 0)'' produces an unsigned zero--
-		the calculation resolves to 0<sup>-</sup>,
+		the calculation resolves to 0<sup>−</sup>,
 		but as it's a [=top-level calculation=],
 		it's then censored to an unsigned zero.
 
 		On the other hand, ''calc(1 / calc(-5 * 0))'' produces −∞,
 		same as ''calc(1 / (-5 * 0))''--
-		the inner calc resolves to 0<sup>-</sup>,
+		the inner calc resolves to 0<sup>−</sup>,
 		and as it's not a [=top-level calculation=],
 		it passes it up unchanged to the outer calc to produce −∞.
 		If it was censored into an unsigned zero,