Color: added support for add color values using uppercase (#21687)

* Color: added support for add color values using uppercase

* Update Color.html

* Update Color.html

* Update Color.html

* Update Color.html

* Update Color.html

Author: puxiao

docs/api/en/math/Color.html

@@ -310,7 +310,7 @@ <h3>[method:Color setStyle]( [param:String style] ) </h3>
 		Translucent colors such as "rgba(255, 0, 0, 0.5)" and "hsla(0, 100%, 50%, 0.5)" are also accepted,
 		but the alpha-channel coordinate will be discarded.<br /><br />
 
-		Note that for X11 color names, multiple words such as Dark Orange become the string 'darkorange' (all lowercase).
+		Note that for X11 color names, multiple words such as Dark Orange become the string 'darkorange'.
 		</p>
 
 		<h3>[method:Color setColorName]( [param:String style] ) </h3>

docs/api/zh/math/Color.html

@@ -303,7 +303,7 @@ <h3>[method:Color setStyle]( [param:String style] ) </h3>
 		半透明颜色例如 "rgba(255, 0, 0, 0.5)" and "hsla(0, 100%, 50%, 0.5)" 也能支持,
 		但是alpha通道的值将会被丢弃。<br /><br />
 
-		注意，对于X11颜色名称，多个单词(如暗橙色)变成字符串“darkorange”(全部是小写字母)。
+		注意，对于X11颜色名称，多个单词(如暗橙色)变成字符串“darkorange”。
 		</p>
 
 		<h3>[method:Color setColorName]( [param:String style] ) </h3>

src/math/Color.js

@@ -264,7 +264,7 @@ class Color {
 	setColorName( style ) {
 
 		// color keywords
-		const hex = _colorKeywords[ style ];
+		const hex = _colorKeywords[ style.toLowerCase() ];
 
 		if ( hex !== undefined ) {