[ENHANCEMENT] BDD French prefixes not fully highlighted (e.g. “Étant donné que”, “Et que”)

[khaledlim]

Robot Framework 7.x officially supports extended French BDD prefixes such as:
Étant donné que, Et que, Mais que, etc. (as documented in RF 7.3 release notes).

However, in VS Code with RobotCode, only the first part of these prefixes
(e.g. Étant donné, Et, Mais) is highlighted as a BDD keyword, while the trailing
part (que, qu') is treated as part of the keyword call.

This creates a visual inconsistency, even though execution works correctly.

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Issue related:
robotframework/robotframework#5150

given_prefixes = ['Étant donné', 'Étant donné que', "Étant donné qu'", 'Soit', 'Sachant que', "Sachant qu'", 'Sachant', 'Etant donné', 'Etant donné que',
"Etant donné qu'", 'Etant donnée', 'Etant données']
when_prefixes = ['Lorsque', 'Quand', "Lorsqu'"]
then_prefixes = ['Alors', 'Donc']
and_prefixes = ['Et', 'Et que', "Et qu'"]
but_prefixes = ['Mais', 'Mais que', "Mais qu'"]

@d-biehl