[RFC 0145] Doc-comments (NixOS#145)

Co-authored-by: figsoda <[email protected]>
Co-authored-by: Anderson Torres <[email protected]>
Co-authored-by: gilice <[email protected]>
Co-authored-by: Florian Klink <[email protected]>
Co-authored-by: Mykola Orliuk <[email protected]>
Co-authored-by: asymmetric <[email protected]>
Co-authored-by: Lassulus <[email protected]>
Co-authored-by: Robert Hensing <[email protected]>
Co-authored-by: Silvan Mosberger <[email protected]>
Co-authored-by: Adam Joseph <[email protected]>