Allow accessing list of issues directly

[muan]

👋 This pull request adds a reader for @failures so users can access them directly, and use the Issue to construct their report if they wish to do so, like what #523 wanted to do.

In our use case, we mostly want to avoid Proofer from raising a generic RuntimeError, and so we will be printing out the errors ourselves. I initially accessed #failed_tests for this, but found that we'd want to group results with path. Since #failed_test gives us issue.to_s, we will have to manually parse it back. Having #failures would be more convenient and gives developers flexibility around reporting.

It'd also be good to decouple the checks in #run into another method so it can be called without raise/logger. I thought I'd start small for now. Thoughts?

cc @gjtorikian 😬

[codecov-io]

Codecov Report

Merging #538 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #538      +/-   ##
==========================================
+ Coverage    98.6%   98.61%   +<.01%     
==========================================
  Files          30       30              
  Lines        1935     1943       +8     
==========================================
+ Hits         1908     1916       +8     
  Misses         27       27

Impacted Files	Coverage Δ
spec/html-proofer/proofer_spec.rb	100% <100%> (ø)	⬆️
lib/html-proofer/runner.rb	99.05% <100%> (ø)	⬆️

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[gjtorikian]

Sure, this works for me. I'll release this as a new minor version of the library soon. Thanks!