Log Message:
lang/janet: Update to 1.26.0

## 1.26.0 - 2023-01-07

- Add `ffi/malloc` and `ffi/free`. Useful as tools of last resort.
- Add `ffi/jitfn` to allow calling function pointers generated at runtime from
  machine code.  Bring your own assembler, though.
- Channels can now be marshalled. Pending state is not saved, only items in the
  channel.
- Use the new `.length` function pointer on abstract types for lengths. Adding
  a `length` method will still work as well.
- Support byte views on abstract types with the `.bytes` function pointer.
- Add the `u` format specifier to printf family functions.
- Allow printing 64 integer types in `printf` and `string/format` family
  functions.
- Allow importing modules from custom directories more easily with the `@`
  prefix to module paths. For example, if there is a dynamic binding
  :custom-modules that is a file system path to a directory of modules, import
  from that directory with `(import @custom-modules/mymod)`.
- Fix error message bug in FFI library.