v0.8.4

🎉 Hello world, I'm a new release for better work!

1. Standardize $0 handling (#99).
2. Fix bindkey to ^J not working normally (#93).
3. Fix exiting the replace mode was not working (#100).
4. Remove unused code in zvm_readkeys.
5. Fix entering insert mode was corrupted occasionally (#94).
6. Fix entering visual mode was currupted occasionally (#103).
7. Fix S surround was not working (#104).
8. Support to custom highlight foreground (#108).
9. Support syntax highlighting with external editor (#109).

This release provides important updates and bug fixes. Welcome to update to this version!