Revert "ripgrep: Set app program name"

This reverts commit 9fbcf91b3c.

Broke OfBorg's eval checks. :(
See <9fbcf91b3c (commitcomment-47236552)>.

pkgs/tools/text/ripgrep/default.nix

@@ -44,6 +44,5 @@ rustPlatform.buildRustPackage rec {
     homepage = "https://github.com/BurntSushi/ripgrep";
     license = with licenses; [ unlicense /* or */ mit ];
     maintainers = with maintainers; [ tailhook globin ma27 zowoq ];
-    mainProgram = "rg";
   };
 }