Modernize using clang-tidy

The following checks were ran:
    modernize-use-auto
    modernize-use-bool-literals
    modernize-use-nullptr
    modernize-use-override
1 job for master in 14 minutes and 18 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #4858
flatpak
flatpak

00:14:18