Backport PR
#10231: Fix set_next_input with prompt_toolkit 1.0.10...
Backport PR
#10231: Fix set_next_input with prompt_toolkit 1.0.10
Closes gh-10229
Please don't merge this just yet.
jonathanslenders I discovered after updating that we can no longer set text in the buffer with a `pre_run` function, because `pre_run_callables` reset the buffer immediately after that. I've worked around this by adding another callable to `pre_run_callables` which sets the text that I want, but I don't know if this is the right way to do it, or whether it works with previous releases of prompt_toolkit.
