Checkout release branch in docs (#1128)

## Summary
Checkout release branch in docs

## Detailed description
- Addresses: [6434852](https://nvbugspro.nvidia.com/bug/6434852)
- Adds a macro that ensures that the checkout command points to the
correct branch.

---------

Signed-off-by: Alex Millane <amillane@nvidia.com>

Author: alexmillane

docs/_ext/isaaclab_arena_doc_tools.py

@@ -20,23 +20,18 @@
 
 
 def isaaclab_arena_git_clone_code_block(app: Sphinx, _: Any, source: list[str]) -> None:
-    """Replaces the :isaaclab_arena_git_clone_code_block: directive with a code block.
-    The output git clone command depends on whether we're in release or internal mode.
-    """
+    """Replaces the :isaaclab_arena_git_clone_code_block: directive with a code block."""
 
     def replacer(_: Any) -> str:
-        release_state = app.config.isaaclab_arena_docs_config["released"]
-        internal_git_url = app.config.isaaclab_arena_docs_config["internal_git_url"]
-        external_git_url = app.config.isaaclab_arena_docs_config["external_git_url"]
-        if release_state:
-            git_clone_target = external_git_url
-        else:
-            git_clone_target = internal_git_url
-        print(f"git_clone_target: {git_clone_target}")
+        git_url = app.config.isaaclab_arena_docs_config["git_url"]
+        # smv_current_version is the ref of a per-version build; empty for local `make html`.
+        docs_ref = getattr(app.config, "smv_current_version", "") or "main"
+        repo_dir = git_url.rstrip("/").rsplit("/", 1)[-1].removesuffix(".git")
         return f"""
 .. code-block:: bash
 
-    git clone {git_clone_target}
+    git clone --branch {docs_ref} --recurse-submodules {git_url}
+    cd {repo_dir}
 
 """
 

docs/conf.py

@@ -164,8 +164,7 @@
 
 isaaclab_arena_docs_config = {
     "released": released,
-    "internal_git_url": "git@github.com:isaac-sim/IsaacLab-Arena.git",
-    "external_git_url": "UNDECIDED",
+    "git_url": "git@github.com:isaac-sim/IsaacLab-Arena.git",
     "internal_code_link_base_url": "https://github.com/isaac-sim/IsaacLab-Arena",
     "external_code_link_base_url": "UNDECIDED",
 }

docs/pages/quickstart/installation.rst

@@ -54,10 +54,7 @@ Both flavors follow the same workflow — clone, sync, activate, run; only the
 
 Clone the repository:
 
-.. code-block:: bash
-
-    git clone --recurse-submodules https://github.com/isaac-sim/IsaacLab-Arena.git
-    cd IsaacLab-Arena
+:isaaclab_arena_git_clone_code_block:
 
 Sync the environment and activate it, picking the flavor that matches your
 workflow:
@@ -162,10 +159,6 @@ installation options.
 
 :isaaclab_arena_git_clone_code_block:
 
-.. code-block:: bash
-
-    git submodule update --init --recursive
-
 2. **Launch the docker container:**
 
 :docker_run_default: