Add comment for night mode search keyword translations

    <string name="keywords_display">screen touchscreen</string>

    <string name="keywords_display_brightness_level">dim screen touchscreen battery</string>

    <string name="keywords_display_auto_brightness">dim screen touchscreen battery</string>

    <!-- Search keywords for display light/dark theme: dark theme, night mode, dim screen, invert brightness [CHAR LIMIT=NONE] -->

    <string name="keywords_display_night_mode">dark theme night mode dim screen invert brightness</string>

    <string name="keywords_display_wallpaper">background personalize customize display</string>

    <string name="keywords_display_font_size">text size</string>