feat: make MatchDirectories clearer

[caarlos0]

setting a bool is a bit weird, and I never know what the behavior will be without reading the godoc.

I propose splitting that option into 2 new options, which hopefully have more self-explanatory-er names.

[codecov]

Codecov Report

Merging #15 (779a8a5) into main (db715ee) will decrease coverage by 1.67%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #15      +/-   ##
==========================================
- Coverage   83.67%   82.00%   -1.68%     
==========================================
  Files           2        2              
  Lines          98      100       +2     
==========================================
  Hits           82       82              
- Misses          9       11       +2     
  Partials        7        7              

Impacted Files	Coverage Δ
glob.go	80.64% <100.00%> (-2.69%)	⬇️

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[erikgeiser]

Yeah, that's much better. It would also be possible for MatchDirectoryIncludesContents and MatchDirectoryAsFile to be OptFuncs themselves such that they don't have to be called. WDYT?