Zsh completion has bogus #compdef value

[WhyNotHugo]

Describe the bug

The auto-generated completion files for zsh have a bogus #compdef directive so zsh won't apply them for the keyring command.

To Reproduce

> python -m keyring  --print-completion zsh | head
#compdef __main__.py

# AUTOMATICALLY GENERATED by `shtab`


_shtab___main___py_commands() {
  local _commands=(
    
  )
  _describe '__main__.py commands' _commands

Expected behavior

Should read #compdef keyring.

Environment

• OS: Alpine Linux

Additional context

I'm adding completion scripts to the downstream Alpine package. This generation of completion needs to happen before the actual packaging phase, I'm using a temporary virtualenv to install keyring:

python3 -m venv --clear --without-pip --system-site-packages .tempenv
.tempenv/bin/python3 -m installer .dist/keyring-$pkgver-py3-none-any.whl
.tempenv/bin/python3 -m keyring --print-completion zsh > keyring.bash
.tempenv/bin/python3 -m keyring --print-completion zsh > keyring.zsh

[WhyNotHugo]

Looks like $0 is unconditionally used for the completion script, but this doesn't make sense when the value is __main__.py.

Using .tempenv/bin/keyring --print-completion zsh > keyring.zsh produces the correct results.