Fix warnings in svgsym.cabal
Support multiple GHC versions in builds
Clean up sourcehut build manifest
Use Nixpkgs's getExe for formatters
Bump Nix flake and update Cabal file
Use `use flake` in .envrc
Validate symbol regular expression
This checks that the regular expression is valid before attempting to
actually use it.
Extend allowed base versions
Mainly to allow building with GHC 8.10.
Minor readme fix
The Sourcehut Markdown renderer doesn't seem to support `sh-session`.
Use `console` instead.
Only export the `main` function
Add autogen-modules to Cabal file
Change package category
Also rename Cabal file to match package name.
Always use GHC 9.0.2
There is no need to build with other versions for now since we are
providing an executable, not a library.