How to create completions for multiple CLI on the same Formula?

[sestegra]

Output of brew config

HOMEBREW_VERSION: 4.2.9
ORIGIN: https://github.com/Homebrew/brew
HEAD: e5fefd73cd97cd36ae3af29551f529ae59b333d6
Last commit: 2 days ago
Core tap JSON: 21 Feb 10:49 UTC
HOMEBREW_PREFIX: /home/linuxbrew/.linuxbrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 16
Homebrew Ruby: 3.1.4 => /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/vendor/portable-ruby/3.1.4/bin/ruby
CPU: 16-core 64-bit unknown_0x6_0xba
Clang: N/A
Git: 2.43.2 => /home/linuxbrew/.linuxbrew/bin/git
Curl: 7.81.0 => /bin/curl
Kernel: Linux 5.15.0-94-generic x86_64 GNU/Linux
OS: Ubuntu 22.04.3 LTS (jammy)
Host glibc: 2.35
/usr/bin/gcc: 11.4.0
/usr/bin/ruby: N/A
glibc: N/A
gcc@11: N/A
gcc: 13.2.0
xorg: N/A

Output of brew doctor

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Warning: Some installed formulae are deprecated or disabled.
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Description of issue

In the following formula, I found a method to create completion from executable, but it writes the output to the same file name with the Formula name.

https://github.com/Homebrew/homebrew-core/blob/30201ee50326628ad4370f8169921316d8fbd8a7/Formula/r/regclient.rb#L26

How to fix this Formula to get the 3 completion files created instead of only one for now and to get bash completions that are missing as well?

[ZhongRuoyu]

Homebrew/homebrew-core#163549 should fix this.