fix(list): update the docs

Author: MPopov

projects/igniteui-angular/src/lib/core/styles/themes/schemas/light/_list.scss

@@ -185,9 +185,9 @@ $_bootstrap-list: extend(
 /// @property {Map} item-text-color-hover [igx-color: ('grays', 900)] - The list item text color.
 /// @property {Map} item-text-color-active [igx-color: ('grays', 900)] - The active list item text color.
 ///
-/// @property {Color} item-subtitle-color [igx-color: ('grays', 600)] - The list item subtitle color.
-/// @property {Color} item-subtitle-color-hover [igx-color: ('grays', 600)] - The list item subtitle hover color.
-/// @property {Color} item-subtitle-color-active [igx-color: ('grays', 600)] - The list item subtitle active color.
+/// @property {Color} item-subtitle-color [igx-color: ('grays', 800)] - The list item subtitle color.
+/// @property {Color} item-subtitle-color-hover [igx-color: ('grays', 800)] - The list item subtitle hover color.
+/// @property {Color} item-subtitle-color-active [igx-color: ('grays', 800)] - The list item subtitle active color.
 ///
 /// @property {Color} item-action-color [igx-color: ('grays', 600)] - The list item action color.
 /// @property {Color} item-action-color-hover [igx-color: ('grays', 600)] - The list item action hover color.