sad: comment out the broken build

I cannot mark this package broken in a way that doesn't break OfBorg.

pkgs/top-level/all-packages.nix

@@ -14757,7 +14757,13 @@ in
 
   rubberband = callPackage ../development/libraries/rubberband { };
 
+  /* This package references ghc844, which we no longer have. Unfortunately, I
+     have been unable to mark it as "broken" in a way that the ofBorg bot
+     recognizes. Since I don't want to merge code into master that generates
+     evaluation errors, I have no other idea but to comment it out entirely.
+
   sad = callPackage ../applications/science/logic/sad { };
+   */
 
   safefile = callPackage ../development/libraries/safefile {};