analyze: use println! instead of info! to print rewritten code

[spernsteiner]

3271b3d replaced all prints in c2rust-analyze with info! or other logging calls. This generally makes it easier to filter the debug output. However, using info! for printing the rewritten code adds a prefix to each line:

[INFO @ c2rust-analyze/src/rewrite/mod.rs:349 @ c2rust_analyze::rewrite]: extern crate libc;
[INFO @ c2rust-analyze/src/rewrite/mod.rs:349 @ c2rust_analyze::rewrite]: extern "C" {
[INFO @ c2rust-analyze/src/rewrite/mod.rs:349 @ c2rust_analyze::rewrite]:     fn malloc(_: libc::c_ulong) -> *mut libc::c_void;
[INFO @ c2rust-analyze/src/rewrite/mod.rs:349 @ c2rust_analyze::rewrite]: }

This makes it hard to copy-paste the rewritten code into a separate .rs file for testing or debugging.

This branch changes the output of rewritten code from info! back to println!.