`texdoc --print-completion zsh` will generate something like
```
compdef __texdoc texdoc
__texdoc() {
...
}
```
So put
```
(( $+functions[__texdoc] )) || eval "$(texdoc --print-completion zsh)" && __texdoc
```
can make it out of box for users to avoid add `eval "$(texdoc --print-completion zsh)"` to their zshrc