David Wood e343521276 Add assert_eq! to special-cased macros
Allows for this form of assert_eq! macros:
```rust
assert_eq!(
    left.id, right.id,
    "IDs are not equal: {:?} {:?}",
    left, right
);
```

Also allows for assert! macros to have the format arguments split across
multiple lines even if the assert condition is not simple:
```rust
assert!(
    result >= 42,
    "The result must be at least 42: {:?}",
    result, result.code, context
);
```
2017-12-23 01:06:17 +00:00
..