🧹 update grammars on main

[Felienne]

This one is a bit similar to #5233 (also fixed recently in #5227)

If keywords are translated, they don't automatically move to the grammars, there is a script for that:

python content/yaml_to_lark_utils.py

When the tests run, this script executed, so the tests always work with the latest grammars:

https://github.com/hedyorg/hedy/blob/main/build-tools/github/validate-tests

But these changes are not committed to main, such that the changes to the grammars are not persistent until someone commits them, also leading to problems.