Catch flake-related exception type in REPL
Catch flake-related exception type in REPL

Closes https://github.com/NixOS/nix/issues/5656

rycee/nix,rycee/nix,NixOS/nix,NixOS/nix,NixOS/nix,NixOS/nix,rycee/nix,rycee/nix,rycee/nix,NixOS/nix