Installer hardcodes icons in .desktop file

[superuser-does]

Problem

The installer hardcodes the icons in DrRacket's and Slideshow's desktop files.

• DrRacket's .desktop file:

  Icon=/usr/share/racket/drracket-exe-icon.png

• Slideshow's .desktop file:

  Icon=/usr/share/racket/slideshow-exe-icon.png

As a result, users will not benefit from integrated and comprehensive icon themes such as Papirus which ship with icons for these programs, without manually editing their .desktop files.

Beyond that, it breaks the established approach to icons in desktop Linux.

Remediation

1. The installer should be made to copy raster & vector icons of the appropriate size(s) to a subdirectory of /usr/share/icons/hicolor/. I believe some distributions' packages may already do this, but have not confirmed for certain.
2. The .desktop files should point to the filename without an extension e.g.

   Icon=drracket

   There is the alternative schema of org.racket_lang.Racket that Flathub uses to ship DrRacket (in accordance with Freedesktop's preferences). However, as this installer installs Slideshow as well, I think it is best to stick to just drracket and racket-slideshow - following what others have named slideshow to avoid namespace overlaps.