Improve the error message when an existing config is found

Author: sandydoo

modules/pre-commit.nix

@@ -431,11 +431,13 @@ in
               [ -L "''${GIT_WC}/${cfg.configPath}" ] && unlink "''${GIT_WC}/${cfg.configPath}"
 
               if [ -e "''${GIT_WC}/${cfg.configPath}" ]; then
-                echo 1>&2 "git-hooks.nix: WARNING: Refusing to install because of pre-existing ${cfg.configPath}"
-                echo 1>&2 "    1. Translate ${cfg.configPath} contents to the new syntax in your Nix file"
-                echo 1>&2 "        see https://github.com/cachix/git-hooks.nix#getting-started"
-                echo 1>&2 "    2. remove ${cfg.configPath}"
-                echo 1>&2 "    3. add ${cfg.configPath} to .gitignore"
+                echo 1>&2 "git-hooks.nix: WARNING: Refusing to install because of an existing config at ${cfg.configPath}"
+                echo 1>&2 ""
+                echo 1>&2 "  To migrate the existing config to a Nix configuration:"
+                echo 1>&2 "    1. Translate the contents of ${cfg.configPath} into a Nix configuration."
+                echo 1>&2 "       See https://github.com/cachix/git-hooks.nix#getting-started"
+                echo 1>&2 "    2. Remove ${cfg.configPath}"
+                echo 1>&2 "    3. Add ${cfg.configPath} to .gitignore"
               else
                 if ${boolToString cfg.addGcRoot}; then
                   nix-store --add-root "''${GIT_WC}/${cfg.configPath}" --indirect --realise ${cfg.configFile}