Add .slnx format for solution files

[akunzai]

https://blog.jetbrains.com/dotnet/2024/10/04/support-for-slnx-solution-files/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.75%. Comparing base (d9e59ca) to head (0903448).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #669   +/-   ##
=======================================
  Coverage   68.75%   68.75%           
=======================================
  Files          43       43           
  Lines        1072     1072           
  Branches      143      143           
=======================================
  Hits          737      737           
  Misses        268      268           
  Partials       67       67           

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