generator: replace snake_case with make_ident

[senekor]

[no important files changed]

[senekor]

A lot of template files changed here, but the output generally stays the same. A couple actual test files changed (only the names of the test functions), the diff is here.

[senekor]

I noticed that the "no important files changed" workflow didn't do its job here. Wild guess: it doesn't work because there are multiple test files changed. In the workflow, this line will be executed multiple times:

echo "important_files_changed=${changed}" >> "$GITHUB_OUTPUT"

So the variable GITHUB_OUTPUT is defined multiple times? I adon't know how github handles this, it may do something random like concatinate all values with commas or similar. If that was the case, the following check won't work anymore:

steps.check.outputs.important_files_changed == 'true'

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EDIT: I checked an I was wrong. It generally works with multiple changes as well:
#1971

So, I don't know why it didn't work this time.