Convert NaiveDate::{from_yo|from_isoywd} to return Result

[pitdicker]

cc @Zomtir. I would like to depend on these methods when working on the Parsed type, and you don't seem to have started on them yet.

[codecov]

Codecov Report

Attention: Patch coverage is 98.93617% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 94.33%. Comparing base (f0e6695) to head (03727e8).

Files	Patch %	Lines
src/naive/date/mod.rs	97.67%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            0.5.x    #1460   +/-   ##
=======================================
  Coverage   94.33%   94.33%           
=======================================
  Files          37       37           
  Lines       17004    17011    +7     
=======================================
+ Hits        16040    16047    +7     
  Misses        964      964           

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[pitdicker]

Simplified from_isoywd a bit and made that into a commit that can apply to the main branch.

[djc]

Nit, would suggest the following:

return Err(match week == 0 || week > 53 {
    true => Error::InvalidArgument,
    false => Error::DoesNotExist,
});

[pitdicker]

For the next time just say 'Use match'. I should know by now 😆.

[pitdicker]

I'll keep this PR open a little longer until we have a new merge of main with the 0.5.x branch.