Incorrect `unreachable_code` lint for loops in `try_blocks`

[varkor]

#![feature(try_blocks)]

pub fn foo() {
    let _: Result<(), ()> = try {
        loop {
            // anything here
        }
    };
}

Here, the entire loop expression is reported unreachable, despite not being so.
This is similar to #54165, and probably has the same underlying issue.

[jonas-schievink]

Looks very similar to #54165