Regex are a crude tool for analyzing whether some code *calls* a
particular function. Spidermonkey has Reflect.parse() that returns
the AST of the passed in code, which allows for a much more precise
check for javascript.
The old script is still used for C code, where i18n-affecting changes
are much rarer.
Based heavily on Philip Chimento's mozjs migration script at
https://gitlab.gnome.org/ptomato/moz60tool.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1941>