- Format ghc-supported-languages module
- Add an args check with help
- All extensions should be registered
- Exclude known languages
- Rename exceptions to langsAsExts
- Rename executable to ghc-supported-extensions
- Use explicit import lists, except for prelude
- Don't use dieNoVerbosity
- Move to exes/GhcSupportedExtensions.hs
- Handle the zero args case gracefully
- Satisfy fourmolu
- We're checking KnownExtension
- Avoid _ in registered pattern match
- Mention language editions
- Add a note about missing language editions