This is a mess. The version is AUR is still outdated and also doesn't
install anymore. Fedora 38 carries the latest version of it so use that
now. Keep the old steps in case we need to switch again in the future.
* SingleExecutor: added TODOs
* test `SingleExecutor` with files and project
* SingleExecutor: process markup files after code when scanning project
* TestSingleExecutor: generate scoped files before calling executor
* CI-unixish.yml: added `--output-on-failure` to CTest call
* helpers.cpp: improved error reporting in `~ScopedFile()`
* use unique filenames in executor tests to avoid collisions
* fixed `functionStatic` selfcheck warnings
* added `Settings::useSingleJob()` and use it instead of checking `jobs` or `jointSuppressionReport`
* extracted single job execution into `SingleExecutor`
* moved `reportStatus()` from `CppCheckExecutor` to Èxecutor
* TestSingleExecutor: improved tests
* added testing of markup extension handling in executors
* cleaned up includes based on `include-what-you-use`
* testsingleexecutor.cpp: suppress `performance-unnecessary-value-param` clang-tidy warnings
* ProcessExecutor: send color via pipe instead of applying it beforehand
* do not unconditionally apply colors to output / disable all colors in tests / adjusted tests for changed output behavior
* fixed precision loss in `Executor::reportStatus()`
* fixed `naming-varname` selfcheck warnings