Add a "web" translation module for docs & landing page

[soleuniverse101]

As I understand, there are currently only 2 modules for translations : core and qt.

I'm suggesting creating a third one that would be named web, which would contain translation strings related to Anki's landing page and for its docs, which are not always up to date AFAIK (for example the French one isn't even in the same format). Note that I thought of this when I saw this issue ankitects/anki-landing-page#53, but I thought that it may be overkill to add a module only for the landing page, so I was thinking that one module for the landing page and for the docs could be worth it. I also considered the fact that Anki's current translation system makes it easy to see which strings's translations were forgotten, for instance if docs related to a new feature were added.

I'm making this issue because I'm not sure if that's the best option, given the fact that docs are significant in size, and I'm not sure if translation files originally targeted at translating the app would be best to translate documentation documents.

What do you think of this ? How would we go about progressively indexing strings from the docs into Anki's translation system ?

A rough idea would be to separate the translation strings of the docs into paragraphs related to specific concepts. Here are examples of sections separated by concepts (in this page) :

[GithubAnon0000]

Related: ankitects/anki-manual#337

[soleuniverse101]

I made a proof of concept at https://github.com/soleuniverse101/anki-manual-i18n-poc using Google's Comprensive Rust book (https://github.com/google/comprehensive-rust) as inspiration. It's based on the packages made available by https://github.com/google/mdbook-i18n-helpers.

It parses the "sections/blocks" of each page and associates it to a locale string in a template used to generate translation files for each language. I think that it's a nice way of doing it because docs will stay more or less in the same structure whatever the language, though it still leaves translators some freedom to rephrase paragraphs nicely as long as they convey the same info.

You can check the result at https://soleuniverse101.github.io/anki-manual-i18n-poc/intro.html by changing the language to French using the top-right corner. (I only translated a few strings as it's meant to be an example of what it could be like at the end...)

For images, a cool thing is that mdbook-i18n-helpers also parses urls as translatable elements, therefore we could also specify different links for images (e.g. showing a page with Anki in the target language).

An obvious drawback with such an endeavor is the massive process of migrating the already available Anki manuals in other languages to the desired format. However I think that it could be done progressively, while keeping the current translated docs at the moment. Still, in the long run, having a single source of docs (the English version) upstream, with translated versions that follow the same structure, and whose translation strings are immediately updated when the original version changes would help keeping docs consistent and up-to-date as Anki keeps receiving new features. Also, it's not exactly a retranslation from zero, some of the docs roughly follow the structure of the https://docs.ankiweb.net/ version (such as the French one, which only has an outdated style, or the Chinese one, which is already a perfect replica). Therefore for some of them at least, the job will mainly be copy & paste. Though as mentioned in ankidroid/ankidroiddocs#101 (comment), it could still need proof reading and a non negligeable effort from translators to try and use the old docs to not have to rewrite everything from scratch while migrating entries one-by-one.

Do you think that it would be worth it ? If so I would love to take part in putting this "system" in place. (We would need to update https://github.com/ankitects/anki-manual and also create a repo for the translation module associated to Pontoon)