[docs] Docs for sky check specific cloud (#3558)

docs

docs/source/getting-started/installation.rst

@@ -164,6 +164,10 @@ section :ref:`below <cloud-account-setup>`.
  If your clouds show ``enabled`` --- |:tada:| |:tada:| **Congratulations!** |:tada:| |:tada:| You can now head over to
  :ref:`Quickstart <quickstart>` to get started with SkyPilot.
 
+.. tip::
+
+ To check credentials only for specific clouds, pass the clouds as arguments: :code:`sky check aws gcp`
+
 .. _cloud-account-setup:
 
 Cloud account setup

sky/cli.py

@@ -2862,7 +2862,7 @@ def _down_or_stop(name: str):
  progress.refresh()
 
 
-@cli.command()
+@cli.command(cls=_DocumentedCodeCommand)
 @click.argument('clouds', required=False, type=str, nargs=-1)
 @click.option('--verbose',
  '-v',
@@ -2881,6 +2881,16 @@ def check(clouds: Tuple[str], verbose: bool):
 
  The enabled clouds are cached and form the "search space" to be considered
  for each task.
+
+ Examples:
+
+ .. code-block:: bash
+
+ # Check credentials for all supported clouds.
+ sky check
+ \b
+ # Check only specific clouds - AWS and GCP.
+ sky check aws gcp
  """
  clouds_arg = clouds if len(clouds) > 0 else None
  sky_check.check(verbose=verbose, clouds=clouds_arg)