Tips-N'-Tricks: fix symlink for zsh completion
Tips-N'-Tricks: fix symlink for zsh completion

From `Library/Contributions/brew_zsh_completion.zsh`:

````bash
````

Then it should give symlinked file name of `_brew` instead of being just `brew_zsh_completion.zsh`

Closes #48897.

Signed-off-by: Dominyk Tiller <53e438f55903875d07efdd98a8aaf887e7208dd3@gmail.com>

filcab/homebrew,filcab/homebrew,filcab/homebrew,filcab/homebrew