This makes these tools usable in a pipe.
You can run
```fish
some-long-command | fish_clipboard_copy
```
to copy some command's output to your clipboard, and
```fish
fish_clipboard_paste | some-other-command
```
To feed your clipboard to some command.
Ubuntu's fish package on WSL 1 has xsel as recommended dependency,
even though there is no X server available. This change makes us
use Windows' native clipboard even when xsel is installed.
- clip.exe is used to copy to the Windows clipboard
- There's no binary for pasting from the Windows clipboard so
`Get-Clipboard` from powershell is used as a workaround. The
superflous carriage return is stripped from the output.
When this switched over from directly piping commandline to storing
its output and using printf, I inadvertently always added a trailing
newline. That's probably annoying.
Note that this will now always *remove* a trailing newline (because
the command substitution does). That will barely make a
difference (because trailing newlines are quite unusual in the
commandline) and will probably feel better than keeping it - we could
even make a point of removing trailing whitespace in general.
Fixes#6927
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.
I hate doing this but I am tired of touching a fish script as part of
some change and having `make style` radically change it. Which makes
editing fish scripts more painful than it needs to be. It is time to do
a wholesale reformatting of these scripts to conform to the documented
style as implemented by the `fish_indent` program.
