Improve i18n link references in docs

[azdanov]

At the moment it's a very hard work to keep the prefixes (/, /de, /es, /fr, etc) and id references (#x86_64-microarchitecture-level-support, #x86_64-mikroarchitektur-level-unterstützung, #soporte-de-nivel-de-microarquitectura-x86_64, #support-du-niveau-de-microarchitecture-x86_64, etc) in sync across translations.

It would be good to figure out a way to minimize the risk of forgetting to update them when updating either by using relative paths instead of absolute and by using English heading id's everywhere instead of localized ones.

• https://docs.astro.build/en/guides/markdown-content/#heading-ids
• https://docs.astro.build/en/guides/internationalization/#create-links

[ptcodes]

@azdanov you're right by saying that it could be solved by using relative paths instead of absolute ones. So /ru/installation/installation_on_root/ becomes ../installation/installation_on_root/

And there is a way of using English ids across translations with the following plugin:
https://github.com/imcuttle/remark-heading-id

Then a heading in an English source becomes:

## x86_64 Microarchitecture Level Support {#x86_64-microarchitecture-level-support}

And in every translation (German, etc.) you can use:

## x86_64-Mikroarchitektur-Level-Unterstützung {#x86_64-microarchitecture-level-support}

Fragment links everywhere (#x86_64-microarchitecture-level-support) are now locale-independent.

It will require a lot of changes across every page... but in the long run will save time and prevent errors.