refactor: simplify to io::Result

[EdJoPaTo]

Simplifies the code, logic stays exactly the same.

[codecov]

Codecov Report

Attention: Patch coverage is 44.44444% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 89.4%. Comparing base (3b002fd) to head (fe2e184).

Files	Patch %	Lines
src/backend/termwiz.rs	0.0%	7 Missing ⚠️
src/backend/crossterm.rs	0.0%	1 Missing ⚠️
src/backend/termion.rs	0.0%	1 Missing ⚠️
src/backend/test.rs	88.8%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1016   +/-   ##
=====================================
  Coverage   89.4%   89.4%           
=====================================
  Files         61      61           
  Lines      15430   15430           
=====================================
  Hits       13799   13799           
  Misses      1631    1631           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.