SUMMARY
Quick open is a useful feature. However, I am missing an option to exclude certain directories or file extensions.
For example, my repository contains Sphinx documentation, and quick open also shows all documentation build artifacts. This can be quite problematic: If I have a file named `api.rst`, building the docs would also generate an artifact named `api.rst.txt`. Now it could happen that you accidentally open and edit the `.txt` file which has the same content as the `.rst` equivalent, but it will be overwritten with the next build cycle and all changes are lost.
So it would be quite helpful to be able to exclude the build directory from quick open, not only to prevent inadvertently opening the wrong file, but also to get a cleaner overview. My quick open panel is often spammed with compiled objects.

STEPS TO REPRODUCE
1. Clone a repository that contains Sphinx documentation
2. Import it into KDevelop
3. Build the documentation (`make html`)
4. Trigger quick open

OBSERVED RESULT
All documentation build artifacts will show up.

EXPECTED RESULT
Only relevant project files should be displayed. Therefore, an option in the settings would be required to exclude certain file types or directories. (Alternatively, though more complex, it could also be possible to read the .gitignore file and not show objects that aren't part of the revision control, but as KDevelop also supports versioning systems other than git this might not be a straightforward solution.)

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.22
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.85.0
Qt Version: 5.15.3
Kernel Version: 5.11.0-27-generic (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
Since KDevelop is a large application, the option I am requesting might already exist at some hidden place. If so, please point me at it and forgive the false issue :)