allow specifying separate outputs for reporters

[srnwk]

Description

Extends the command-line arguments to allow specifying a filter of reporters
to which the output filename applies: --out=junit[junit-report.xml],xml[report.xml],console[log.txt]
The old syntax --out=filename still works, being treated like --out=*[filename].
This allows sending for example JUnit output to a file, and still having the console reporter output to the console: -r=junit,console -o=junit[report.xml] (since no output file has a matcher that matches the console reporter, it uses its default, stdout).

(Should there be an explicit way to specify stdout as well? Possibly using - as the filename, like many *nix tools do?)

TODO:

• update documentation
• API for setting these from main
• tests, coverage

GitHub Issues

See #627

[codecov]

Codecov Report

Merging #669 (b0b48ca) into dev (b7c21ec) will decrease coverage by 0.03%.
The diff coverage is 81.48%.

@@            Coverage Diff             @@
##              dev     #669      +/-   ##
==========================================
- Coverage   92.19%   92.16%   -0.04%     
==========================================
  Files           2        2              
  Lines        2127     2156      +29     
==========================================
+ Hits         1961     1987      +26     
- Misses        166      169       +3     

Impacted Files	Coverage Δ
doctest/parts/doctest.cpp	91.67% <80.76%> (-0.03%)	⬇️
doctest/parts/doctest_fwd.h	97.70% <100.00%> (ø)

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[nickdademo]

Very nice! Looking forward to this one ;)

[beyse]

Also looking forward to it

[vitaliy-ostapchuk93]

any updates on this? would be really great to use 💯