Chloggen clarify termininology

[djaglowski]

This is intended as a quick follow up to #372. Mostly it just standardizes on the terms "entry/entries" instead of "chlog/chlogs".

[codecov]

Codecov Report

Patch coverage: 83.47% and project coverage change: +0.63% 🎉

Comparison is base (e6e68a6) 62.07% compared to head (bdbad0c) 62.70%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #375      +/-   ##
==========================================
+ Coverage   62.07%   62.70%   +0.63%     
==========================================
  Files          48       48              
  Lines        2344     2392      +48     
==========================================
+ Hits         1455     1500      +45     
- Misses        741      743       +2     
- Partials      148      149       +1     

Files Changed	Coverage Δ
chloggen/cmd/update.go	64.70% <55.00%> (-5.30%)	⬇️
chloggen/internal/chlog/entry.go	86.20% <94.28%> (+4.66%)	⬆️
chloggen/cmd/new.go	78.78% <100.00%> (ø)
chloggen/cmd/validate.go	88.00% <100.00%> (+3.78%)	⬆️
chloggen/internal/config/config.go	100.00% <100.00%> (ø)

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