tiny fix: heading in docs not showing correctly (#71743)
The "Examples" heading was not being rendered correctly [on this docs
page](https://nextjs.org/docs/app/api-reference/file-conventions/page#displaying-content-based-on-params).
All this does is fix the whitespace character to allow the MDX to be
rendered properly.
Co-authored-by: JJ Kasper <jj@jjsweb.site>
