docs: Fix DialogTrigger -> TooltipTrigger typo in custom trigger section

[makotot]

https://react-aria.adobe.com/Tooltip#custom-trigger

Fixed a typo in the Tooltip documentation where DialogTrigger was incorrectly used instead of TooltipTrigger in the custom trigger section.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

🧢 Your Project:

[yihuiliao]

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