fix: `forgit::diff` not working if repo path contains spaces

[max-ae]

Check list

~- [ ] I have performed a self-review of my code~ ~- [ ] I have commented my code in hard-to-understand areas~ ~- [ ] I have made corresponding changes to the documentation~

Description

https://github.com/wfxr/forgit/commit/5093c185329488448aa6e631d3e751a402729a15 broke forgit::diff / gd if the path to the repo contains spaces. This fixes the issue by wrapping the repo path in quotes.

Type of change

• [x] Bug fix
• [ ] New feature
• [ ] Refactor
• [ ] Breaking change
• [ ] Documentation change

Test environment

• Shell
  • [x] bash
  • [x] zsh
  • [ ] fish
• OS
  • [ ] Linux
  • [x] Mac OS X
  • [ ] Windows
  • [ ] Others: