[LANGUAGE] Allow for translations of erroneous programs

[Felienne]

(This is a redo of #4867 which contained some commits now already on main)

Since #4828 translation features are more prominently visible, so I figured we need to do a bit better. This actually changes some conceptual assumptions, so let's document here:

• Programs that have a ParseError or contain Placeholders, or have indentation issues, still cannot be translated (since they can't be parsed and then we don't have a tree to work wtih)
• All other errors however create a parsetree with error nodes, and thus... can just be translated keeping the error nodes, so that is what we now do!

How to test

Try a program with an error production, f.e. in German, level 7:
repeat 3 times 'Hedy macht Spaß!'

Main shows an error:

This PR translates the code:

[ghost]

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[Felienne]

(oops closed by mistake!)

[jpelay]

It works nicely! This is very cool!!

[mergify]

Thank you for contributing! Your pull request is now going on the merge train (choo choo! Do not click update from main anymore, and be sure to allow changes to be pushed to your fork).