Strings using single quotes are not detected

[Zylann]

Only double quotes are considered by the extractor, because according to Python convention, they are the ones containing actual text. I also didn't think about single quotes since I never use them.
Despite all that, I've seen tr being used on single-quoted strings in GDScript inside other plugins, and these strings could be IDs.
These strings are either undetected, or cause extraction errors.