Add explicit arg REPLACE to the callers of `shell-command-on-region'.

Add explicit arg REPLACE to the callers of `shell-command-on-region'.

* lisp/simple.el (shell-command-on-region): Doc fix.

* lisp/emulation/vi.el (vi-shell-op):
* lisp/emulation/vip.el (vip-execute-com, ex-command):
* lisp/emulation/viper-cmd.el (viper-exec-bang):
* lisp/emulation/viper-ex.el (ex-command): Add non-nil arg REPLACE to
the call of `shell-command-on-region'.

* lisp/mh-e/mh-alias.el (mh-alias-local-users): Add non-nil arg REPLACE to
the call of `shell-command-on-region'.

Fixes: debbugs:14637