Add missing "///" to update.md

[nathan-osman]

On the "Update Data with FastAPI", towards the bottom of the page, one of the "/// tip" is missing the "///":

/// tip
Before SQLModel 0.0.14, the method was called `hero.dict(exclude_unset=True)`, but it was renamed to 
`hero.model_dump(exclude_unset=True)` to be consistent with Pydantic v2.

## Update the Hero in the Database

This PR adds the missing line and restores correct rendering of the page.

[github-actions[bot]]

📝 Docs preview for commit 7cced3cdef7f4497e93a4a8bd6cdb8985d57f150 at: https://4e1ac74e.sqlmodel.pages.dev

[alejsdev]

Hi @nathan-osman thanks for the interest :smile: but apparently this one was handled in another PR, so we'll close this one. Thank you! :rocket: