Add language selector on site (fixes #64)

[Nutomic]

There are probably better ways to implement some things, but its not easy to find good docs for js/ts.

[Nutomic]

I tried some libraries for this, but none of them worked well, partly because our language identifiers are in different formats. And mnc (Manchu) is essentially a dead language with 20 native speakers, so we can easily remove it.

[dessalines]

Here's the library I'm using in lemmy-ui: https://github.com/LemmyNet/lemmy-ui/blob/main/src/shared/utils.ts#L431

Then all you need are the codes:

export const languages = [
  { code: "ca" },
  { code: "en" },
...

[dessalines]

Looks good... does the rustdoc pages work with cookies, or with a url param?

[dessalines]

Here's the library I'm using in lemmy-ui: https://github.com/LemmyNet/lemmy-ui/blob/main/src/shared/utils.ts#L431

Then all you need are the codes:

export const languages = [
  { code: "ca" },
  { code: "en" },
...

[dessalines]

I don't think we have any params-based things here, might just require setting the language cookie then reloading.

[Nutomic]

That will also work, but sometimes its useful to link people to a specific language version of the site, and thats much easier if you can just use the selection and then copy the url.

[dessalines]

pry don't need the startsWith here?

[Nutomic]

Using equality instead, it didnt work because i18n.language was en-GB, and language only contained en, so it wouldnt match.

[Nutomic]

I didnt check with rustdoc, you would probably have to change the languge separately.

About the iso-639-1 library, its missing some language names, and also in Lemmy itself its broken. Like 中文_Hant is nonsense, it should be 文言. Same for Norsk bokmål_NO, should just be Norsk bokmål. And some language names are in lower case for some reason, like suomi or euskara. mnc isnt translated at all (again, we can remove that lang). Defining it like this in our code works much better, and i would do it the same way in Lemmy.