5504: Remove useless typedef in c++ r=Jupeyy a=Chairn
## Checklist
- [ ] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [ ] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)
Co-authored-by: Chairn <chairn.nq@hotmail.fr>
> Warn when a local variable shadows another local variable or parameter.
Found one actual bug in graphics_threaded.cpp
Should reduce confusion in the future when reading source code