Improve error messages for color functions that aren't in sass:color (#1482)

Author: nex3

spec/core_functions/modules/color.hrx

@@ -315,7 +315,7 @@ Error: Undefined function.
 a {b: color.adjust-hue(#abcdef, 10)}
 
 <===> error/adjust_hue/error
-Error: The function adjust-hue() isn't in the new module system.
+Error: The function adjust-hue() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $hue: 10)
 
@@ -333,7 +333,7 @@ More info: https://sass-lang.com/documentation/functions/color#adjust-hue
 a {b: color.lighten(#abcdef, 10%)}
 
 <===> error/lighten/error
-Error: The function lighten() isn't in the new module system.
+Error: The function lighten() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $lightness: 10%)
 
@@ -351,7 +351,7 @@ More info: https://sass-lang.com/documentation/functions/color#lighten
 a {b: color.darken(#abcdef, 10%)}
 
 <===> error/darken/error
-Error: The function darken() isn't in the new module system.
+Error: The function darken() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $lightness: -10%)
 
@@ -369,7 +369,7 @@ More info: https://sass-lang.com/documentation/functions/color#darken
 a {b: color.saturate(#abcdef, 10%)}
 
 <===> error/saturate/error
-Error: The function saturate() isn't in the new module system.
+Error: The function saturate() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $saturation: 10%)
 
@@ -387,7 +387,7 @@ More info: https://sass-lang.com/documentation/functions/color#saturate
 a {b: color.desaturate(#abcdef, 10%)}
 
 <===> error/desaturate/error
-Error: The function desaturate() isn't in the new module system.
+Error: The function desaturate() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $saturation: -10%)
 
@@ -405,7 +405,7 @@ More info: https://sass-lang.com/documentation/functions/color#desaturate
 a {b: color.opacify(#abcdef, 0.5)}
 
 <===> error/opacify/error
-Error: The function opacify() isn't in the new module system.
+Error: The function opacify() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $alpha: 0.5)
 
@@ -423,7 +423,7 @@ More info: https://sass-lang.com/documentation/functions/color#opacify
 a {b: color.fade-in(#abcdef, 0.5)}
 
 <===> error/fade_in/error
-Error: The function fade-in() isn't in the new module system.
+Error: The function fade-in() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $alpha: 0.5)
 
@@ -441,7 +441,7 @@ More info: https://sass-lang.com/documentation/functions/color#fade-in
 a {b: color.transparentize(#abcdef, 0.5)}
 
 <===> error/transparentize/error
-Error: The function transparentize() isn't in the new module system.
+Error: The function transparentize() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $alpha: -0.5)
 
@@ -459,7 +459,7 @@ More info: https://sass-lang.com/documentation/functions/color#transparentize
 a {b: color.fade-out(#abcdef, 0.5)}
 
 <===> error/fade_out/error
-Error: The function fade-out() isn't in the new module system.
+Error: The function fade-out() isn't in the sass:color module.
 
 Recommendation: color.adjust(#abcdef, $alpha: -0.5)