Adds the Murex shell (https://murex.rocks) to the set of shells
supported by 'zoxide init'.
Changes:
- templates/murex.txt: new init script template implementing
PWD/Prompt hooks via 'event onPrompt name=command-completion',
__zoxide_z/zi helpers with empty-PARAMS handling, and clean
return-1 on no-match queries.
- src/shell.rs: wires the template + two tests:
* murex_murex (functional, runs the rendered init under murex -c),
parameterized across all opts combinations and gated by the
nix-dev feature so it only runs in the project's nix-shell
* murex_template_has_direct_path_handling (string assertions on
the rendered template, runs always)
- src/cmd/cmd.rs: adds Murex to the InitShell enum
- src/cmd/init.rs: imports Murex and adds the match arm
- shell.nix: pins Murex to v7.2.1001 via a surgical overrideAttrs
on the existing pkgs.murex (only this single package changes; the
nixpkgs pin itself stays put). v7.0 introduced the
'command-completion' onPrompt interrupt that the prompt/PWD hooks
depend on, so the version bundled with the current nixpkgs pin
(v6.4.2063) is too old to source the rendered init.
Completion stubs in contrib/completions/ are not touched directly;
they regenerate via build.rs when the InitShell enum changes.
Closes#1085
Jeff Melton