use C99 bool from stdbool.h instead of int everywhere

Trac:
Username: cyberpunks

changed milestone to %Tor: unspecified

added c99 coccinelle component::core tor/tor milestone::Tor: unspecified parent::13260 priority::medium reporter::cyberpunks severity::normal status::new technical-debt tor-client type::defect labels

When returning a boolean from a function, bool is the best we can do.

In a struct, a 1-bit field is better (unsigned int foo : 1).

I'm fine with returning a bool from functions that are logically boolean, but we shouldn't change the convention for functions where "0" indicates success and "-1" indicates an error.

moved to tpo/core/tor#27661 (closed)