tweak(ped): add further documentation for SET_ENABLE_HANDCUFFS

[MadsLeander]

Adds further documentation for SET_ENABLE_HANDCUFFS and what it does.

Note: The example might be a little long, but I sincerely believe it's better than the following, as it showcases the native in an actual use case.

-- Sets handcuffs on the player's ped
SetEnableHandcuffs(PlayerPedId(), true)

If requested, I can make a short video showing/proving the example and my findings; I'm just too lazy to do it this second. Let me know if anything needs to be changed.

[JayPaulinCodes]

Overall I like this very much, my only suggestion would be to maybe explore some code comments for the example, seeing as it's a bit more than just the native call and instead is an actual use case, it may be beneficial to add some code comments to help explain exactly what the example is achieving with the native in question.

Other than that 2 cents of mine, all looks good to me.