Replace libdash pretty printer with shasta?

Would it be possible to merge the libdash and shasta pretty printers? There have been multiple PRs (#31, #32) that have had to be duplicated across shasta, libdash ocaml and libdash python.

The necessary way of doing this would be to remove the libdash python pretty printer, and instead require a pass through shasta, since shasta already needs to be able to print its typed ast.

Referenced [here](https://github.com/binpash/shasta/pull/3#issuecomment-2495610640).