remove generic filter check for non-generic event (aka almost all events)

Note: in https://github.com/ZZZank/FastEvent/issues/2 , the issue author pointed out that EventBus in NeoForge cannot be transformed, so patches in FastEvent will basically be completely ignored. Installing FastEvent in NeoForge will not cause any performance improvement and/or regression

Fix a potential crash due to registering methods with non-trivial return type. (Mods in 1.16+ MC version are mostly doing a good job in being standardized, so this crash will, basically, never happen)

Fix a potential crash due to registering methods with non-trivial return type. (Mods in 1.16+ MC version are mostly doing a good job in being standardized, so this crash will, basically, never happen)

Fix a potential crash due to registering methods with non-trivial return type. (Mods in 1.16+ MC version are mostly doing a good job in being standardized, so this crash will, basically, never happen)