docs: fix maritalk description at https://python.langchain.com/docs/integrations/chat/ All chat models section (#31314)

…ntegrations/chat/ All chat models section

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docs/docs/integrations/chat/maritalk.ipynb

@@ -8,8 +8,6 @@
     "\n",
     "# Maritalk\n",
     "\n",
-    "## Introduction\n",
-    "\n",
     "MariTalk is an assistant developed by the Brazilian company [Maritaca AI](https://www.maritaca.ai).\n",
     "MariTalk is based on language models that have been specially trained to understand Portuguese well.\n",
     "\n",