treewide: add meta.mainProgram to packages with a single binary

The nixpkgs-unstable channel's programs.sqlite was used to identify
packages producing exactly one binary, and these automatically added
to their package definitions wherever possible.

pkgs/development/web/function-runner/default.nix

@@ -15,6 +15,7 @@ rustPlatform.buildRustPackage rec {
 
   meta = with lib; {
     description = "A CLI tool which allows you to run Wasm Functions intended for the Shopify Functions infrastructure";
+    mainProgram = "function-runner";
     homepage = "https://github.com/Shopify/function-runner";
     license = licenses.asl20;
     maintainers = with maintainers; [ nintron ];