Cargo: Enable doctests

We barely write any comments, but if we do then we should make sure that they compile and work

Author: Turbo87

Cargo.toml

@@ -15,7 +15,7 @@ opt-level = 2
 
 [lib]
 name = "cargo_registry"
-doctest = false
+doctest = true
 
 [[test]]
 name = "all"