Pass return value to WeaponSwitchPost, WeaponCanUsePost, WeaponCanSwitchToPost #2532

SDKHook_ReloadPost already passes the engine function's return value into the callback:
void OnReloadPost(int weapon, bool bSuccess)

The following hooks also return meaningful bool values, but their Post callbacks do not expose them:
SDKHook_WeaponSwitchPost
SDKHook_WeaponCanUsePost
SDKHook_WeaponCanSwitchToPost

Plugins need the real outcome e.g., whether a weapon switch actually succeeded. Adding the return value as an extra callback parameter, consistent with ReloadPost, would cover this cleanly.

@Kenzzer this might be a quick addition during the khook migration, or I'm happy to submit a PR once that branch lands.