fix(git-node): clarify remote configuration error message (#1001)

Author: aduh95

lib/session.js

@@ -382,10 +382,14 @@ export default class Session {
       cli.setExitCode(1);
     }
     if (!upstream) {
-      cli.warn('You need to configure the remote repository for Node.js core.');
+      cli.warn('You have not told git-node what remote name you are trying to land commits on.');
       cli.separator();
-      cli.info(
-        '1. First, add the Node.js core repository as a remote (if not already added):\n' +
+      const remoteName = runSync('git', ['remote', '-v'])
+        .match(/^(\S+)\s+(?:https:\/\/github\.com\/|git@github\.com:)nodejs\/node\.git \(\S+\)\r?$/m)?.[1];
+      cli.info(remoteName
+        ? `You likely want to run the following:\n\n  $ ncu-config set upstream ${remoteName}`
+        : 'The expected repository does not seem to appear in your local config.\n' +
+        '1. First, add the Node.js core repository as a remote:\n' +
         '   $ git remote add upstream https://github.com/nodejs/node.git\n\n' +
         '2. Then, tell git-node to use this remote for syncing:\n' +
         '   $ ncu-config set upstream upstream\n\n' +