micro-optimization: use int8 for enums

[drakkan]

not sure if it's worth it

[codecov]

Codecov Report

Merging #338 (80c40b8) into main (59dc591) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #338   +/-   ##
=======================================
  Coverage   85.86%   85.86%           
=======================================
  Files          11       11           
  Lines        1563     1563           
=======================================
  Hits         1342     1342           
  Misses        152      152           
  Partials       69       69           

Impacted Files	Coverage Δ
asciiconverter.go	94.59% <ø> (ø)
client_handler.go	86.53% <ø> (ø)

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[fclairamb]

I don't see any reason not to do it