Site fixes

[devdrops]

Found at https://docs.zendframework.com:

• Scroll down to the bottom in some pages hides part of the navigation menu:
  • Before:
  • After:
• Home always point to the same page instead of index, as well as the breadcrumb DOCS step (there is no link to the Docs index page, except at the footer):
  • Detail:

[froschdesign]

@devdrops Problems with the theme of the docs should be reported here: https://github.com/zendframework/zf-mkdoc-theme/issues

[devdrops]

@froschdesign my bad, I'm moving the issue to the right repository, thanks!