Update RL Tutorial (#9008)

* Add blurb on installing dspy from source

Author: Ziems

docs/docs/tutorials/rl_multihop/index.ipynb

@@ -12,6 +12,11 @@
     "\n",
     "```bash\n",
     "> pip install -U arbor-ai\n",
+    "```\n",
+    "\n",
+    "You may also have to install DSPy from the main branch:\n",
+    "```bash\n",
+    "> pip install -U git+https://github.com/stanfordnlp/dspy.git@main\n",
     "```"
    ]
   },

docs/docs/tutorials/rl_papillon/index.ipynb

@@ -15,7 +15,12 @@
     "For this tutorial, you will also need [DSPy's Arbor RL framework](https://github.com/Ziems/arbor) which you can install with:\n",
     "```bash\n",
     "> pip install -U arbor-ai\n",
-    "```"
+    "```\n",
+    "\n",
+    "You may also have to install DSPy from the main branch:\n",
+    "```bash\n",
+    "> pip install -U git+https://github.com/stanfordnlp/dspy.git@main\n",
+    "```\n"
    ]
   },
   {