Added a single line
"To drop x items, type a number and then the item hotkey."
To the multidrop screen.
Merge branch 'GUI_Dropping' of https://github.com/Soyweiser/Cataclysm-DDA into Soyweiser-GUI_Dropping
Merge branch 'master' of https://github.com/CleverRaven/Cataclysm-DDA