Fix various lint issues

[jonjohnsonjr]

1. Typo
2. Missing package doc comment
3. Tautological conditional

[codecov-commenter]

Codecov Report

Merging #1010 (4e72261) into main (9cf3ed4) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##             main    #1010   +/-   ##
=======================================
  Coverage   75.33%   75.33%           
=======================================
  Files         107      107           
  Lines        5036     5036           
=======================================
  Hits         3794     3794           
  Misses        701      701           
  Partials      541      541           

Impacted Files	Coverage Δ
internal/and/and_closer.go	100.00% <ø> (ø)
internal/estargz/estargz.go	100.00% <ø> (ø)
internal/gzip/zip.go	88.57% <ø> (ø)
internal/verify/verify.go	100.00% <ø> (ø)
pkg/v1/cache/cache.go	52.83% <0.00%> (ø)

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