meson: install static documentation files
meson: install static documentation files

related to #4086

i3/i3,Airblader/i3,i3/i3,Airblader/i3,i3/i3,Airblader/i3-original,Airblader/i3-original,stapelberg/i3,Airblader/i3-original,i3/i3,Airblader/i3-original,stapelberg/i3,Airblader/i3,stapelberg/i3,Airblader/i3,Airblader/i3-original,stapelberg/i3