Resolve lint warnings for rustc >=v1.75

[goulart-paul]

Resolves new linter warnings in v1.75, most of which relate to redundant imports or unused functions. Fix for #83.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 91.83673% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 85.78%. Comparing base (77a61b5) to head (67e1241).

Files	Patch %	Lines
src/solver/implementations/default/info_print.rs	88.57%	4 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
+ Coverage   85.67%   85.78%   +0.10%     
==========================================
  Files          62       62              
  Lines        4425     4431       +6     
==========================================
+ Hits         3791     3801      +10     
+ Misses        634      630       -4     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.