Improve error message when --template target is a package

Fixes #148

lib/remote-template.js

@@ -2,7 +2,7 @@
  * @import {OptionsOfJSONResponseBody} from 'got';
  * @import {ErrorMessageInfo} from './types/error-message';
  * @import {Options, Template} from './types/options';
- * @import {ApplicationElmJson} from './types/content';
+ * @import {ElmJson, ApplicationElmJson} from './types/content';
  * @import {Path} from './types/path';
  */
 const https = require('node:https');
@@ -153,19 +153,37 @@ I need this file to determine the rest of the configuration.`
   });
 
   const elmJson = parseElmJson(response.body, repoName);
+
+  if (elmJson.type === 'package') {
+    const referenceAsUrl = template.reference ? `/${template.reference}` : '';
+
+    throw new ErrorMessage.CustomError(
+      // prettier-ignore
+      'INVALID TEMPLATE ELM.JSON TYPE',
+      // prettier-ignore
+      `I found the ${chalk.yellow('elm.json')} associated with ${chalk.yellow(repoName)} repository on GitHub,
+but it is of type ${chalk.red('package')} when I need it to be of type ${chalk.yellow('application')}.
+
+Maybe you meant to target the ${chalk.cyan('example')} or the ${chalk.cyan('preview')} folder in that repository?
+
+    elm-review --template ${repoName}${referenceAsUrl}/example
+    elm-review --template ${repoName}${referenceAsUrl}/review`
+    );
+  }
+
   return elmJson;
 }
 
 /**
  * @param {string} body
  * @param {string} repoName
- * @returns {ApplicationElmJson}
+ * @returns {ElmJson}
  */
 function parseElmJson(body, repoName) {
   try {
     const json = /** @type {unknown} */ (JSON.parse(body));
 
-    return /** @type {ApplicationElmJson} */ (json);
+    return /** @type {ElmJson} */ (json);
   } catch (error) {
     throw new ErrorMessage.CustomError(
       // prettier-ignore