Use bit32 instead of bit as namespace for bit library

[ccuser44]

bit32 is used in vanilla Lua and Luau meanwhile bit is used in LuaJIT. I think the vanilla naming should be preferred and Luau would treat it better. Not sure though if it would hurt LuaJITs optimizations.

[Rerumu]

LuaJIT probably won't care, so if bit32 is better for readability I'm all for it.