The pid the `grep -v` is trying to eliminate is not at the end
of the line.
`all_tmux_processes` produces the following output (for example):
```
tmux 32069 29270
```
Here the first number is the pid and the second -- the uid. So, since
the idea of `number_tmux_processes_except_current_server` is to eliminate
32069 from consideration, it should look for "<SPACE>PID<SPACE>".
When counting the number of running tmux processes, count only those
that belong to the current user.
`tmux a` shows as a separate process (must be the client process) and
thus needs to be excluded from the calculation as well. The previous
exclusion of `tmux source` was also incorporated.
Do not count `tmux source-file .tmux.conf` as a tmux process when checking if
other tmux server is running.
Previously, this caused interpolation command not to be inserted into
`status-right` because `tmux source-file` was falsely detected as another tmux
server.
Sergei Gerasenko