If a command fails, print the pipestatus in red instead of yellow and
don't print the status of the last process again. See #6375.
Also use $fish_color_status for coloring status consistently.
Also use __fish_pipestatus_with_signal to print SIGPIPE instead
of a numeric code on e.g.: yes | less +q
[ci skip]
This runs build_tools/style.fish, which runs clang-format on C++, fish_indent on fish and (new) black on python.
If anything is wrong with the formatting, we should fix the tools, but automated formatting is worth it.
