nav: browser back navigation does not jump to the correct position

[nibau]

This could be related to #476

I've recently noticed this issue with a markdown hugo page containing anchor links going to a different area within the same page.
e.g.

[SomeLink](#someheading)

...

## someheading

Let's say we have a page X with heading a.
When visiting X and clicking an anchor link #a the scroll position jumps to a.
When now using the browser back button, the expected native behavior is, that the scrolling position jumps back to the position it was before clicking the link. When clicking the browser forward button afterwards, the scrolling position should then jump back to the position it was before clicking the back button.

Example:

1. Visit https://gohugo.io/hugo-modules/use-modules/#use-a-module-for-a-theme -> position jumps to "Use a Module for a Theme"
2. Navigate/change URL to https://gohugo.io/hugo-modules/use-modules/#update-modules -> position jumps to "Update Modules"
3. Click browser back button -> position jumps back to "Use a Module for a Theme"
4. Click browser forward button -> scroll position back to "Update Modules"

When using the relearn theme I noticed that 3. and 4. do not seem to work properly, i.e. the scrolling position does not change when navigating back and forth between different anchors on the same page.

Example:

1. Visit https://mcshelby.github.io/hugo-theme-relearn/basics/installation/
2. Navigate/change URL to https://mcshelby.github.io/hugo-theme-relearn/basics/installation/#create-your-first-content-pages -> position jumps to "Create your first content pages"
3. Try browser back button -> nothing happens

(I have tested with Firefox and Edge (Chromium))

[McShelby]

I can confirm this but it will take a while to fix.