scel is not included by default on linux anymore

[TatriX]

Since this change which was included in 3.14, scel is not built by default anymore.

In order to fix it you either need to rebuild SuperCollider as explained in the docs.
Or simply add scel to your sclang_conf.yaml:

1. Find where sclang_conf.yaml is located: run sclang and evaluate Platform.userConfigDir.
   You will get something like ~/.config/SuperCollider.
   Search for sclang_conf.yaml there.
2. Add path to the directory containing scel.quark to includePaths:
   It should look something like this:

includePaths:
    -   /home/tatrix/.local/share/SuperCollider/downloaded-quarks/wslib
    -   /home/tatrix/.emacs.d/scel
excludePaths:
    []
postInlineWarnings: false
excludeDefaultPaths: false

And that's it! Restart scel for example by calling (sclang-start) or and it should start working again.