Can't link to top of module documentation page

[malaire]

The top autogenerated H1 title of each module documentation page doesn't have id, so there is no way to link to top of module documentation page.

For example link https://package.elm-lang.org/packages/elm/core/latest/List doesn't go to top of the page when that link is used within package.elm-lang.org, and there is currently no id to create a link like https://package.elm-lang.org/packages/elm/core/latest/List#top-of-the-page

I suggest that an id is added to that title, which won't clash with any potential other ids. Perhaps _top_ would be OK, as it's unlikely any package would publish function named _top_.

top would clash with function top or type Top, and -top- would clash with example below, so those two can't be used.

## `top`

[malaire]

Or perhaps better fix would be to use the code shown at https://package.elm-lang.org/packages/elm/browser/latest/Browser-Dom#setViewport for every URL which doesn't have hash.