check-meta: fix 'predicate' instructions

In the code examples for using `allowUnfreePredicate` and
`allowNonSourcePredicate`, we use `lib.getName` (which removes
the version) and not the local `getName` (which keeps the version).

pkgs/stdenv/generic/check-meta.nix

@@ -181,7 +181,7 @@ let
 
       Alternatively you can configure a predicate to allow specific packages:
         { nixpkgs.config.${predicateConfigAttr} = pkg: builtins.elem (lib.getName pkg) [
-            "${getName attrs}"
+            "${lib.getName attrs}"
           ];
         }
     '';
@@ -222,23 +222,23 @@ let
 
              $ export NIXPKGS_ALLOW_INSECURE=1
              ${flakeNote}
-        b) for `nixos-rebuild` you can add ‘${getName attrs}’ to
+        b) for `nixos-rebuild` you can add ‘${lib.getName attrs}’ to
            `nixpkgs.config.permittedInsecurePackages` in the configuration.nix,
            like so:
 
              {
                nixpkgs.config.permittedInsecurePackages = [
-                 "${getName attrs}"
+                 "${lib.getName attrs}"
                ];
              }
 
         c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
-           ‘${getName attrs}’ to `permittedInsecurePackages` in
+           ‘${lib.getName attrs}’ to `permittedInsecurePackages` in
            ~/.config/nixpkgs/config.nix, like so:
 
              {
                permittedInsecurePackages = [
-                 "${getName attrs}"
+                 "${lib.getName attrs}"
                ];
              }