docs: Document granularity of timestamps
docs: Document granularity of timestamps

This information is necessary to make any use of these fields.

abooij/wayland,sir-murray/wayland,abooij/wayland,eyolfson/wayland,bitfactor/wayland,tulcod/wayland,eyolfson/wayland,sir-murray/wayland,eyolfson/wayland,tulcod/wayland,bitfactor/wayland,mchalupa/wayland,sir-murray/wayland,bitfactor/wayland,tulcod/wayland,mchalupa/wayland,mchalupa/wayland,abooij/wayland