[Suggestion] Add "Related" section to References entries

[adevade]

I originally wrote this as a discussion on the cms repo, might be suited better here.

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It would be nice if below the info of the Modifier, Tag and Variable, there was a "Related" section with similar functions.

For example, if I'm viewing the days_ago modifier, between the content and the "Docs Feedback" widget there could be a "Related modifiers" listing links to hours_ago, minutes_ago, months_ago, etc...

I can guess and find it in the sidebar, but it's not always as similar naming as in the example above.

[adevade]

Another example:

https://statamic.dev/modifiers/list

Could link to Related:
https://statamic.dev/modifiers/join
https://statamic.dev/modifiers/ampersand_list