The previous commit already fixed the user-visible lag, but there's still a
problem with multiple background git processes consuming resources calculating
diffs that we are never going to show. Improve this by terminating those
processes (by sending them a TERM signal).
Unfortunately this is only possible on Linux and Mac, so Windows users will have
to live with the higher CPU usage. The recommended workaround is to not use
"diff.algorithm = histogram".
In 5a3049485c we changed the execution of shell commands to use an interactive
shell (-i), because this allows users to use aliases or shell functions, which
is a nice convenience.
Since then, however, many users have reported problems with lazygit not coming
back to the foreground after executing a shell command. Some users report that
appending "; exit" to the end of the command line solves this. I don't really
understand what the cause of this problem was, or why appending "; exit" solves
it, but if it helps, let's do it.
Also, use the user's shell (from the SHELL env variable) instead of bash. Both
of these together allow users to use their shell aliases or shell functions in
the interactive command prompt.
