feat(cli): add command description

packages/vant-cli/src/index.ts

@@ -11,27 +11,49 @@ import { changelog } from './commands/changelog';
 import { buildSite } from './commands/build-site';
 import { commitLint } from './commands/commit-lint';
 
-command('dev').action(dev);
+command('dev')
+  .description('Run webpack dev server')
+  .action(dev);
 
-command('lint').action(lint);
+command('lint')
+  .description('Run eslint and stylelint')
+  .action(lint);
 
-command('clean').action(clean);
+command('test')
+  .description('Run unit tests through jest')
+  .option(
+    '--watch',
+    'Watch files for changes and rerun tests related to changed files'
+  )
+  .option(
+    '--clearCache',
+    'Clears the configured Jest cache directory and then exits'
+  )
+  .action(test);
+
+command('clean')
+  .description('Clean all dist files')
+  .action(clean);
 
 command('build')
+  .description('Compile components in production mode')
   .option('--watch', 'Watch file change')
   .action(build);
 
-command('release').action(release);
+command('release')
+  .description('Compile components and release it')
+  .action(release);
 
-command('changelog').action(changelog);
+command('build-site')
+  .description('Compile site in production mode')
+  .action(buildSite);
 
-command('build-site').action(buildSite);
+command('changelog')
+  .description('Generate changelog')
+  .action(changelog);
 
-command('commit-lint').action(commitLint);
-
-command('test')
-  .option('--watch')
-  .option('--clearCache')
-  .action(test);
+command('commit-lint')
+  .description('Lint commit message')
+  .action(commitLint);
 
 parse(process.argv);