Allow silencing/disabling error prints

[Pajn]

The write file has two eprintln! that I'm hitting when using the apollo-compiler create that depends on ariadne.

ariadne/src/write.rs

Line 62 in ad4fe4e

eprintln!("Unable to fetch source '{}': {:?}", Show(src_display), err);

ariadne/src/write.rs

Line 239 in ad4fe4e

eprintln!("Unable to fetch source {src_name}: {err:?}");

Would it be possible to provide a way to silence these error prints?

[zesterer]

Sure, perhaps the error could be forwarded to the caller of Report:::write? Happy to accept a PR for this!