These take a *lot* of time - `pip3` takes 180ms, `pipenv` takes 320ms
on my system.
Note that this removes a number of obsolete workarounds - pip's was
fixed in 2017 (and pip2 is less and less of a thing), pipenv's change
was in 2019.
Since these are packaging tools with access to the internet they
should really be kept up-to-date, so it is unlikely someone still uses
these old versions.
Since 4414d5c888 (in fish 3.0.0) we
don't autoload completions if the command doesn't exist.
So there is no need to check inside the scripts anymore.
Whats more, a few (like pip and cabal) checked `command -q` instead of
`type -q`, meaning they'd fail if someone used a function instead of a
command of that name.
If the *command* actually needs to exist, checks like that are still
warranted, like in `npm` where aliasing it to `nvm` is popular.
A teensy additional bit: Make `sysctl -w` the same as `sysctl
--write`. That description was bogus.
* Add pip completion
* We call native pip completion for fish if pip is installed
* Add pipenv completion
* We call pipenv native completion if pipenv is installed
* Applied changes as requested by @floam
* Changed usage of `test (command -v)` for just `command -sq`
* Add completions for pip2/3
* In some systems pip is not aliased and we have pip2 and pip3
* In those cases, we just load the completions for those commands
* Separate pip2/3 completions in their own file as requested by @floam
