This module defines the supported programming languages for ast-grep.
It provides a set of customized languages with expando_char / pre_process_pattern,
and a set of stub languages without preprocessing.
A rule of thumb: if your language does not accept identifiers like $VAR.
You need use impl_lang_expando! macro and a standalone file for testing.
Otherwise, you can define it as a stub language using impl_lang!.
To see the full list of languages, visit <https://ast-grep.github.io/reference/languages.html>