Make exit code success when Steep has unreported type errors

[pocke]

Probably it fixes #158

problem

Steep exits with status code 1 unexpectedly. The cause is type-checking options.
Steep CLI filters type errors by this option.

steep/lib/steep/drivers/check.rb

Line 56 in 33f507b

source_file.errors.select {|error| target.options.error_to_report?(error) }.each do |error|

But the option does not affect the exit status code.
Becuase it checks target.errors.empty? but target.errors contains unreported type errors.

steep/lib/steep/drivers/check.rb

Line 67 in 33f507b

if project.targets.all? {|target| target.status.is_a?(Project::Target::TypeCheckStatus) && target.no_error? && target.errors.empty? }

solution

Remove unreported type errors from Steep::Project::Target#errors.

[soutaro]

Thanks! 💯