Convert --language option to String instead of LanguageType

[petertrr]

• Convert --language option to String instead of LanguageType
• Improve docs of extra flags feature

[codecov]

Codecov Report

Merging #444 (ee96102) into main (c3fce0e) will increase coverage by 0.15%.
The diff coverage is n/a.

❗ Current head ee96102 differs from pull request most recent head ca62d6d. Consider uploading reports for the commit ca62d6d to get more accurate results

@@             Coverage Diff              @@
##               main     #444      +/-   ##
============================================
+ Coverage     46.61%   46.77%   +0.15%     
  Complexity      150      150              
============================================
  Files            53       52       -1     
  Lines          1772     1766       -6     
  Branches        331      331              
============================================
  Hits            826      826              
+ Misses          814      808       -6     
  Partials        132      132              

Flag	Coverage Δ
unittests	46.77% <ø> (+0.15%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.