Themes: Color adjuster functions are not highlighted in theme variables

[deathaxe]

"l(- 5%)", is highlighted as quoted string.

{
	"variables":
	{
		"text_widget_dark_modifier": "l(- 5%)",
		"text_widget_light_modifier": "l(- 5%)",
	}
}

[FichteFoll]

Nice, didn't know that was possible.