No fall damage with trigger_gravity example

A quick and rough example of how you can make it so the player doesn't take fall damage. This is a method that I made, and based on the quake live cushion, to make more vertical deathmatch maps flow a little better. It's worth noting that Half life seems to calculate fall damage by the amount you fell before the low gravity trigger and adds it on top of the distance fallen after the normal gravity trigger, but also the amount of low gravity seems to play into it as well (I'm not sure the amount and I don't have any type of formula this is just from my testing as well as trial and error), so keep that in mind when using this trick and try accounting for jumping. You can also mess around with different gravity settings to find something that works for your map, like I could've made it a little less noticeable by doing .4 gravity instead of .2 and still not taken damage (without jumping), but really this is kinda a complex and sometimes janky way to do something that should be easier to do with the default tools.