Show that any sound name can be used for OVERRIDE_VEH_HORN

[lighthousey]

This PR aims to show that any sound can be used as a horn hash - given you have the actual name (typically found in *_sounds.dat54.nametable). It's nice to have this kind of stuff transparent and collated in one place to allow for cool little extras, for example, random sounds as horns on a racing server.

For some examples in action see https://youtu.be/RAmpgPQVAxE

local horns = {
    "DLC_XM_Explosions_Orbital_Cannon",
    "DLC_23_2_Cargo_Ship_Horn_Oneshot",
    "DLC_23_2_CBR_2_Train_Horn",
    "DLC_AW_Warhorn_01",
    "DLC_AW_Warhorn_02",
    "DLC_AW_Warhorn_03",
    "DLC_AW_Airhorn_Long_Master",
    "DLC_AW_Airhorn_Short_Master",
    "DLC_HALLOWEEN_BTYPE2_HORN",
    "DLC_Halloween_Horns_Test",
    "LARGE_TRUCK_HORN_1_WRAPPER",
    "WINDSOR_MULTI_HORN",
    "VEHICLES_CAR_HORN_MED_8",
    "VEHICLES_CAR_HORN_LIGHT_5",
    "DLC_Biker_Trailblazers_Horns_01",
    "DLC_Biker_Trailblazers_Horns_02",
    "DLC_Biker_Trailblazers_Horns_03",
    "DLC_Biker_Trailblazers_Horns_04",
    "DLC_Biker_Trailblazers_Horns_05",
    "DLC_Biker_Trailblazers_Horns_06",
    "DLC_Biker_Trailblazers_Horns_07",
    "Tripping_UFO_2_Horn",
    "VEHICLES_HORNS_RUMPO3",
    "tug_horn_master",
    "DLC_Apt_Yacht_Horn",
    "TORO2_HORN_LOUD",
    "brigham_horn",
    "DLC_MP2023_1_VEHICLES_CAR_HORN_GAUNTLET6_1",
    "DLC_MP2023_1_VEHICLES_CAR_HORN_GAUNTLET6_2",
}```