Clarify how Rust treats backslashes at end of line in string literals
Clarify how Rust treats backslashes at end of line in string literals

Rust differs in that behavior from C: In C, the newline escapes are resolved
before anything else, and in Rust this depends on whether the backslash is
escaped itself.

A difference can be observed in the following two programs:

```c
#include <stdio.h>
int main()
{
	printf("\\
n\n");
	return 0;
}
```

```rust
fn main() {
	println!("\\
n");
}
```

The first program prints two newlines, the second one prints a backslash, a
newline, the latin character n and a final newline.

rust-lang/reference,rust-lang/reference