[css-color-5] unresloved percentages issue now solved

Author: svgeesus

css-color-5/Overview.bs

@@ -139,8 +139,6 @@ if the colorspace is [=lch=],
 lightness means the LCH Lightness, which is the same as Lab lightness,
 but different to the HSL Lightness.
 
-Issue: If an adjuster is specified without a percentage, what does its percentage default to?
-
 Only the [=color-adjuster=]s defined for a given [=colorspace=] are available.
 For example, it is not possible to use the HWB [=whiteness=] adjuster unless the colorspace is [=hwb=].
 The alpha adjuster is available on any color space.