Use info! instead of println! in tutorial

When debugging actual Bevy games, you almost always want to use `info!` instead of `println` in order to reduce blocking behavior.

This is not at all obvious to Rust beginners, and showing them how to use `println` misleads them into thinking it's a good pattern to replicate.

This was a simple find-and-replace change for me, and resulted in much faster looping.

Search the tutorial content for uses of Rust's println! macro; the issue does not name a specific file or test. Replace the tutorial's debugging examples with info! where appropriate, then verify the examples still build and teach the intended logging pattern.

Written by the indexing model from the issue text.