All document icons should be earmarked in upper-right corner

All document icons should be earmarked on upper-right corner (upper-right corner folded inwards), so that they are instantly recognizable as documents (as opposed to applications or other types of files).

Instead of


we need


The earmark could even be a bit larger so as to be more clearly distinguishable even at smaller sizes.

This applies to all icons with this "upright rectangular box" shape.