Fix user_migrations_intro saying "GitHub Enterprise Server.com"

[qaisjp]

Why

There is a typo that says "GitHub Enterprise Server.com" on https://docs.github.com/en/[email protected]/rest/migrations/users?apiVersion=2022-11-28#about-user-migrations

What's being changed (if available, include any code snippets, screenshots, or gifs):

Before

After

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