Introduce corresponds macro from openssl-macros

Our rustdocs are miserably broken. We manually link to openssl docs in
most binding definitions, and openssl keeps changing their documentation
URL, so in order to fix everything I'd have to touch every single
binding definition in every single file. Instead, we should use the
`corresponds` macro from the openssl-macros crate which nicely adds a
link to the openssl documentation on our behalf. If the openssl
documentation url ever changes again in the future, a simple dependency
bump should solve the issue.

Cargo.toml

@@ -40,5 +40,6 @@ http = "0.2"
 hyper = { version = "0.14", default-features = false }
 linked_hash_set = "0.1"
 once_cell = "1.0"
+openssl-macros = "0.1.1"
 tower = "0.4"
 tower-layer = "0.3"

boring/Cargo.toml

@@ -69,6 +69,7 @@ kx-client-nist-required = ["kx-safe-default"]
 bitflags = { workspace = true }
 foreign-types = { workspace = true }
 once_cell = { workspace = true }
+openssl-macros = { workspace = true }
 libc = { workspace = true }
 boring-sys = { workspace = true }