[css-color-5] Fix color-mix() grammar, drop <number>, allow adjusters/percentage per component

Author: LeaVerou

css-color-5/Overview.bs

@@ -88,32 +88,35 @@ Mixing colors: the ''color-mix()'' function {#color-mix}
 
 
 <pre class='prod'>
-	<dfn>color-mix()</dfn> = color-mix( <<color>>  <<color>> [ <<number>> | <<percentage>> |
-		[ [=color-adjuster=] [=colorspace=]? ]?] )
+	<dfn>color-mix()</dfn> = color-mix(<<colorspace>>?, <<mix-component>>#{2})
 </pre>
 
 <pre class='prod'>
-	<dfn>colorspace</dfn> = srgb | hsl | hwb | xyz | lab | lch
+	<dfn>&lt;mix-component></dfn> = <<color>> [ <<percentage>> | <<color-adjuster>>+ ]?
 </pre>
 
 <pre class='prod'>
-	<dfn>color-adjuster</dfn> = <<rgb-adjuster>> | <<hsl-adjuster>> | <<hwb-adjuster>> | <<xyz-adjuster>> | <<lab-adjuster>> | <<lch-adjuster>>
-	<dfn>srgb-adjuster</dfn> = red | green | blue
-	<dfn>hsl-adjuster</dfn> = <<hue-adjuster>> | saturation | lightness
-	<dfn>hwb-adjuster</dfn> = <<hue-adjuster>> |  whiteness | blackness
-	<dfn>xyz-adjuster</dfn> = x | y | z
-	<dfn>lab-adjuster</dfn> = lightness | a | b
-	<dfn>lch-adjuster</dfn> = lightness | chroma | <<hue-adjuster>>
-	<dfn>hue-adjuster</dfn> = hue [shorter | longer | increasing | decreasing ]?
+	<dfn>&lt;colorspace></dfn> = srgb | hsl | hwb | xyz | lab | lch
+</pre>
+
+<pre class='prod'>
+	<dfn>&lt;color-adjuster></dfn> = <<rgb-adjuster>> | <<hsl-adjuster>> | <<hwb-adjuster>> | <<xyz-adjuster>> | <<lab-adjuster>> | <<lch-adjuster>>
+	<dfn>&lt;srgb-adjuster></dfn> = red || green || blue
+	<dfn>&lt;hsl-adjuster></dfn> = <<hue-adjuster>> || saturation || lightness
+	<dfn>&lt;hwb-adjuster></dfn> = <<hue-adjuster>> ||  whiteness || blackness
+	<dfn>&lt;xyz-adjuster></dfn> = x || y || z
+	<dfn>&lt;lab-adjuster></dfn> = lightness || a || b
+	<dfn>&lt;lch-adjuster></dfn> = lightness || chroma || <<hue-adjuster>>
+	<dfn>&lt;hue-adjuster></dfn> = hue [shorter | longer | increasing | decreasing | specified ]?
 </pre>
 
 When no [=colorspace=] is specified,
 the mixing is done in the ''lch'' colorspace.
 
-When a plain number or percentage is specified (without a [=color-adjuster=]),
+When a percentage is specified (without a [=color-adjuster=]),
 it applies to all color channels in the given [=colorspace=] equally.
 
-If the plain number or percentage is omitted,
+If the percentage is omitted,
 it defaults to 50% (an equal mix of the two colors).
 
 The [=xyz=] colorspace is CIE XYZ, with a D50 whitepoint, and allows computation to be done