@Contract(pure = true)
  static @NotNull ShadowColor shadowColor(final @NotNull RGBLike rgb, final @Range(from = 0x0, to = 0xff) int alpha) {
    return shadowColor(rgb.red(), rgb.green(), rgb.blue(), alpha);
  }
Create a shadow color from an existing colour plus an alpha value.

@param rgb the existing color
@param alpha the alpha
@return a shadow colour
@since 4.18.0
api/src/main/java/net/kyori/adventure/text/format/ShadowColor.java