i18n: Add support for translating the class reference

[akien-mga]

• Parse .po files from doc/translations/*.po like already done
  with editor/translations/*.po.
• Add logic to register a doc translation mapping in TranslationServer
  and EditorSettings.
• Add DTR() to lookup the doc translation mapping (similar to TTR()).
• Use DTR() to translate relevant strings in EditorHelp.
• Small simplification to TranslationLoaderPO, the path argument was
  not really meaningful.

Depends on #37114 to actually generate the translation catalog and start collecting doc translations on Weblate.

[akien-mga]

Refactored a bit to enforce the dedent().strip_edges() directly in RTR() and thus simplify call sites. Other locations where DocData strings are used now also use RTR().

[akien-mga]

Added a commit (attributed to @ThakeeNathees who wrote it) to fix an issue parsing closing quotes preceded by multiple escaped blackslashes (see #37114 (comment)).

[txj-mssl]

Submitting to weblate is very troublesome. Can you make a configuration file alone? The configuration file downloads the content of weblate and can be freely modified locally.

[txj-mssl]

In this way, even if there is no translation on weblite, I can translate and use it myself.

[akien-mga]

You can download the Weblate .po file for your language, put it in doc/translations/ and recompile the engine (master branch only). But if you're going to spend a few hours translating content in your language, it would be very appreciated if you contributed it on Weblate so that all native speakers of your language can benefit from it.

[txj-mssl]

I tried to modify the Po file today. The built-in documents are displayed correctly, while the details panel does not display Chinese. Why?

[akien-mga]

It's probably not using the DTR() macro, I'll have a look.

[txj-mssl]

Did you find out why?

[akien-mga]

I was on my commute to the office... please have some patience.

[akien-mga]

I can reproduce the issue, but I'm not sure why it happens yet. The translation does work properly, but the Chinese characters aren't display, yet the font used should support them in theory. Investigating further.

[akien-mga]

The problem is somewhere in editor/editor_help.cpp's _add_text_to_rt method, the input is correct (e.g. in my test "Propriété : [u][b]text[/b][/u]\nLe texte à afficher sur l'écran. 汉语"), but the output lacks the Chinese characters.

It's the same method used for the main editor help so both should be using the same font which supports CJK glyphs.

I'll debug further to see where it breaks in that method.

[txj-mssl]

When can this feature be pushed to version 3.2?

[akien-mga]

I don't plan to include it in 3.2, the amount of work necessary from translators to translate all the API reference is huge, and is better focused towards the next version 4.0.

It's of a higher priority that translators finish translating the online documentation before attempting to translate the class reference: https://hosted.weblate.org/projects/godot-engine/godot-docs/

[txj-mssl]

When to fix an incorrectly displayed problem?

[akien-mga]

If you want to hire me to fix problems for you within one hour of their report, you can send me an email with a proposal.

Otherwise let me do my work as time permits, thanks.

[akien-mga]

Here you go, one day's worth of debugging a bigger issue to come up with a workaround... #39123

[txj-mssl]

Sorry, I didn't notice the news

[txj-mssl]

What should I do?

[akien-mga]

Nothing, the PR I opened works it around but it's not a proper fix, the real bug is #39235.