Update hugo shortcode details

What does this MR do?

While looking up the link for the hugo shortcode details to share with someone, I realized we had a lot of examples using the incorrect format. So I did a find and replace to fix all the examples. Everywhere else in the docs is using the correct format. I suspect these are leftover from an earlier version of the guidance, but did not get updated by the script as they were in code blocks or backticks.

Additionally, I stumbled on the Hugo migration guide, which I do not believe we need anymore. Opened !203627 (merged) to remove it.

Related issues

Related to Remove hugo migration guide (!203627 - merged)

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