chore(deps): bump custom/plugins/zsh-abbr from 1105007 to 84f18ab

Bumps [custom/plugins/zsh-abbr](https://github.com/olets/zsh-abbr) from `1105007` to `84f18ab`.
- [Release notes](https://github.com/olets/zsh-abbr/releases)
- [Commits](olets/zsh-abbr@1105007...84f18ab)

---
updated-dependencies:
- dependency-name: custom/plugins/zsh-abbr
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>