launch_shell_job: Move computer to top-level of metadata

The `metadata` passed to the `launch_shell_job` is just supposed to
expose the same input of the `ShellJob` and essentially forward it.
However, the `computer` input was expected to be passed nested inside
the `options` namespace, even though it is defined as a top-level
metadata input. This makes the inputs for `launch_shell_job` dfifferent
from the `ShellJob` causing unnecessary confusion. The `computer` input
should now be specified as a top-level metadata input for the
`launch_shell_job` wrapper as well.

docs/source/howto.rst

@@ -444,15 +444,15 @@ Defining a specific computer
 By default the shell command ran by ``launch_shell_job`` will be executed on the localhost, i.e., the computer where AiiDA is running.
 However, AiiDA also supports running commands on remote computers.
 See the `AiiDA's documentation <https://aiida.readthedocs.io/projects/aiida-core/en/latest/howto/run_codes.html#how-to-set-up-a-computer>`__ for instructions to setting up and configuring a remote computer.
-To specify what computer to use for a shell command, pass it as an option to the ``metadata`` keyword:
+To specify what computer to use for a shell command, pass it as a key to the ``metadata`` argument:
 
 .. code-block:: python
 
     from aiida.orm import load_computer
     from aiida_shell import launch_shell_job
     results, node = launch_shell_job(
         'date',
-        metadata={'options': {'computer': load_computer('some-computer')}}
+        metadata={'computer': load_computer('some-computer')}
     )
     print(results['stdout'].get_content())
 

src/aiida_shell/launch.py

@@ -58,7 +58,7 @@ def launch_shell_job(  # noqa: PLR0913
         generated for each ``CalcJob`` and typically are not of interest to a user running ``launch_shell_job``. In
         order to not confuse them, these nodes are omitted, but they can always be accessed through the node.
     """
-    computer = (metadata or {}).get('options', {}).pop('computer', None)
+    computer = (metadata or {}).pop('computer', None)
 
     if isinstance(command, str):
         code = prepare_code(command, computer, resolve_command)