fix: improve completions

[caarlos0]

setting arg counts and added long description to completions command.

[vercel]

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[codecov]

Codecov Report

Merging #1894 (5aae4a9) into master (c39c820) will increase coverage by 0.12%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1894      +/-   ##
==========================================
+ Coverage   81.65%   81.78%   +0.12%     
==========================================
  Files          73       73              
  Lines        3800     3826      +26     
==========================================
+ Hits         3103     3129      +26     
  Misses        573      573              
  Partials      124      124              

Impacted Files	Coverage Δ
cmd/build.go	100.00% <100.00%> (ø)
cmd/check.go	100.00% <100.00%> (ø)
cmd/completion.go	100.00% <100.00%> (ø)
cmd/init.go	90.47% <100.00%> (+0.47%)	⬆️
cmd/release.go	100.00% <100.00%> (ø)
cmd/root.go	100.00% <100.00%> (ø)

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[github-actions]

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