feat(test): Add cargo_test to test-support prelude

Author: epage

crates/cargo-test-support/src/lib.rs

@@ -73,6 +73,7 @@ pub mod registry;
 pub mod tools;
 
 pub mod prelude {
+    pub use crate::cargo_test;
     pub use crate::ArgLine;
     pub use crate::CargoCommand;
     pub use crate::ChannelChanger;