ref-tables FR-AT reworked

[Bluette-C-Riviere]

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{Summary of the changes}

Description

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Fixes #{issue number}

[TSchmiedlechner]

Hey @Bluette-C-Riviere, thanks for splitting this up! Some general observations:

• The slugs in the file headers should be distinctive
• File names must not contain spaces, those should be removed :)

I will go through the content in more detail later too

[volllly]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[volllly]

Hey, I've just noticed that these files don't have the .md file extension 😅

I think we'll also need to update the slugs in these files to be unique 🤔 @TSchmiedlechner can you confirm/deny that? (EDIT: ok I see you have already mentioned that #260 (comment) 😅)

Also we should remove the content from the reference-table.md so its not duplicated.