docs: Fix typo in quick-start.md

[twlz0ne]

The original command put the article into content/posts, then there is nothing display on the home page.

It does give the First-time users like me a little trouble.

[CLAassistant]

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[bep]

We have moved the Hugo site source to its own repository, so we would appreciate if you could open this PR directly in hugoDocs: https://github.com/gohugoio/hugoDocs/pulls

[twlz0ne]

@bep gohugoio/hugoDocs#628

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.