fix docs: model_calls -> llm_calls in MessagesState in quickstart

[ybillwang]

To make the python definition of MessagesState match the returned value in llm_call

Overview

Updated the Quickstart guide

Type of change

Type: [Fix typo]

Related issues/PRs

Examples:

• closes bind_tools after another bind overwrites bound arguments #456 (will auto-close issue bind_tools after another bind overwrites bound arguments #456 when PR is merged)
• See landing page #789 for context (will reference but not auto-close issue landing page #789)
  -->
• GitHub issue:
• Feature PR:

• Linear issue:
• Slack thread:

Checklist

• [x ] I have read the contributing guidelines
• I have tested my changes locally using docs dev
• All code examples have been tested and work correctly
• I have used root relative paths for internal links
• I have updated navigation in src/docs.json if needed
• I have gotten approval from the relevant reviewers
• (Internal team members only / optional) I have created a preview deployment using the Create Preview Branch workflow

Additional notes

[mdrxy]

TY!