gx: complete the string_colors map (#10634)

Author: metif12

vlib/gx/color.v

@@ -206,9 +206,26 @@ pub fn (c Color) abgr8() int {
 
 const (
 	string_colors = map{
-		'black': black
-		'blue':  blue
-		'red':   red
+		'blue':        blue
+		'red':         red
+		'green':       green
+		'yellow':      yellow
+		'orange':      orange
+		'purple':      purple
+		'black':       black
+		'gray':        gray
+		'indigo':      indigo
+		'pink':        pink
+		'violet':      violet
+		'white':       white
+		'dark_blue':   dark_blue
+		'dark_gray':   dark_gray
+		'dark_green':  dark_green
+		'dark_red':    dark_red
+		'light_blue':  light_blue
+		'light_gray':  light_gray
+		'light_green': light_green
+		'light_red':   light_red
 	}
 )