1. Fixing all reported dead links.
2. Changing `title` value in index.md back to plural form, i.e. "Nodes APIs".
The second change fixed missing child pages. I am not saying I insist on use of plural form but if we want to change it to a singular form then we also have to change `parent` fields in all child pages to correctly refer to valid parent, otherwise all child pages and content is missing.
As for the debate of use APIs vs API (plural vs singular) I just want to point out that right now there are many other parent pages using plural form. If we want to change that then I suggest doing it in separate PR and include other relevant parent pages too.
Closes: #591
Signed-off-by: Lukáš Vlček <lukas.vlcek@aiven.io>
98c7dd29a6