Replace panic in RollHash::set_k with an error

[tmaklin]

Hi, another small PR to facilitate library usage. Hope it's OK.

The current implementations of RollHash will panic for invalid input data when set_k is called. I think it'd be better to return an error so these inputs can be skipped/fixed/inspected etc. so that the panic doesn't crash the entire program if sketchlib is used as a library.

I've implemented this and propagated the errors up to sketch_files, which just unwraps them. Same for sketch_files_inverted. This does break compatibility with previous versions again, though, if the affected functions are used somewhere else.

[codecov]

Codecov Report

❌ Patch coverage is 83.67347% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.01%. Comparing base (af38422) to head (611da60).

Files with missing lines	Patch %	Lines
src/sketch/mod.rs	87.09%	4 Missing ⚠️
src/hashing/aahash_iterator.rs	50.00%	2 Missing ⚠️
src/hashing/nthash_iterator.rs	80.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #86      +/-   ##
==========================================
- Coverage   90.08%   90.01%   -0.07%     
==========================================
  Files          17       17              
  Lines        3974     3977       +3     
==========================================
  Hits         3580     3580              
- Misses        394      397       +3     

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[johnlees]

Thanks Tommi, looks good!

Could you bump the patch version?

[tmaklin]

done!

[mtrsl]

It probably doesn't matter, but the general advice is to define your own error types for library functions to return (manually or using the zero-overhead & transparent library thiserror to make that easier), and use anyhow only in application code to "consume" errors.