removing webpki::Error as return type

[Herbert-Karl]

hi,
following I propose a solution for issue #839. As I am new to Rust and the codebase of rustls, I don't have much confidence, that the change doesn't break API or introduces side effects.
I have run the existing tests and no errors were reported. I haven't fuzzed the changed codebase or did any manual testing.

[ctz]

Thanks! Going to hold this one for the next release, as it's a breaking API change.

[codecov-commenter]

Codecov Report

Merging #858 (a7813d1) into main (d334e5f) will decrease coverage by 0.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main     #858      +/-   ##
==========================================
- Coverage   96.17%   96.16%   -0.02%     
==========================================
  Files          59       59              
  Lines        9406     9407       +1     
==========================================
  Hits         9046     9046              
- Misses        360      361       +1     

Impacted Files	Coverage Δ
rustls/src/anchors.rs	80.95% <66.66%> (-1.31%)	⬇️

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[briansmith]

Thanks for working on this. I just have one suggestion.

[ctz]

Thanks for the contribution here -- recently we've been trying to move away from errors that aren't machine readable because they squashed the cause into a string -- see eg. #1162. This has been fixed in the progress towards that -- see a777077.