Follow-up doc nits from PR #465 (#476)

## Summary

Addresses two nits from the PR #465 review that were approved but not
resolved before merge:

- Use the `python` alias instead of `/isaac-sim/python.sh` in all RL
workflow doc pages
- Remove `--headless` as a default flag in the training command examples

Signed-off-by: Clemens Volk <cvolk@nvidia.com>

Author: cvolkcvolk

docs/pages/example_workflows/reinforcement_learning/step_1_environment_setup.rst

@@ -159,7 +159,7 @@ To validate the environment loads correctly, run one training iteration and chec
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
+   python submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
      --external_callback isaaclab_arena.environments.isaaclab_interop.environment_registration_callback \
      --task lift_object \
      --num_envs 64 \

docs/pages/example_workflows/reinforcement_learning/step_2_policy_training.rst

@@ -14,12 +14,15 @@ builds the environment, and registers it with gym so IsaacLab's script can find
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
+   python submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
      --external_callback isaaclab_arena.environments.isaaclab_interop.environment_registration_callback \
      --task lift_object \
      --num_envs 512 \
-     --max_iterations 12000 \
-     --headless
+     --max_iterations 12000
+
+.. tip::
+
+   Add ``--headless`` to suppress the GUI when running on a headless server.
 
 Checkpoints are written to ``logs/rsl_rl/generic_experiment/<timestamp>/``.
 The agent configuration is saved alongside as ``params/agent.yaml``,
@@ -47,12 +50,11 @@ For example, to train with relu activation and a higher learning rate:
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
+   python submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
      --external_callback isaaclab_arena.environments.isaaclab_interop.environment_registration_callback \
      --task lift_object \
      --num_envs 512 \
      --max_iterations 12000 \
-     --headless \
      agent.policy.activation=relu \
      agent.algorithm.learning_rate=0.001
 
@@ -64,7 +66,7 @@ Launch Tensorboard to monitor progress:
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh -m tensorboard.main --logdir logs/rsl_rl
+   python -m tensorboard.main --logdir logs/rsl_rl
 
 During training, each iteration prints a summary to the console:
 
@@ -104,7 +106,7 @@ Add ``--distributed`` to spread environments across all available GPUs:
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
+   python submodules/IsaacLab/scripts/reinforcement_learning/rsl_rl/train.py \
      --external_callback isaaclab_arena.environments.isaaclab_interop.environment_registration_callback \
      --task lift_object \
      --num_envs 512 \

docs/pages/example_workflows/reinforcement_learning/step_3_evaluation.rst

@@ -47,7 +47,7 @@ Method 1: Single Environment Evaluation
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh isaaclab_arena/evaluation/policy_runner.py \
+   python isaaclab_arena/evaluation/policy_runner.py \
      --policy_type rsl_rl \
      --num_steps 1000 \
      --checkpoint_path logs/rsl_rl/generic_experiment/2026-01-28_17-26-10/model_11999.pt \
@@ -77,7 +77,7 @@ For more statistically significant results, run across many environments in para
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh isaaclab_arena/evaluation/policy_runner.py \
+   python isaaclab_arena/evaluation/policy_runner.py \
      --policy_type rsl_rl \
      --num_steps 5000 \
      --num_envs 64 \
@@ -131,7 +131,7 @@ Create a file ``eval_config.json``:
 
 .. code-block:: bash
 
-   /isaac-sim/python.sh isaaclab_arena/evaluation/eval_runner.py --eval_jobs_config eval_config.json
+   python isaaclab_arena/evaluation/eval_runner.py --eval_jobs_config eval_config.json
 
 .. code-block:: text