Retrieves a post with the provided slug.
The slug is the end of a post's URL that refers to a specific post.
For example, if a post's URL is https:/example.com/blog/post/my-post-slug,
the slug is my-post-slug. The slug is case-sensitive, and is generally derived from the post title,
unless specified otherwise.
This method doesn't return any custom errors, but may return standard errors. Learn more about standard Wix errors.