[New] Document Readline applications not working in 5250

[kadler]

What documenation would you like added?

The Python REPL doesn't work properly (along with anything else that uses GNU Readline) in QSH / QP2TERM. When type a line of text and press enter, it echos only the first character, then when you press enter again, it echos the remainder of the line and executes it.

eg.

 > import foo
   i
 >
   mport foo
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   ModuleNotFoundError: No module named 'foo'
   >>>

The same thing happens with bash:

 > /QOpenSys/pkgs/bin/bash
   bash: cannot set terminal process group (30651): A system call received a par
   ameter that is not valid.
   bash: no job control in this shell
   bash-5.1$
 > echo foo
   e
 >
   cho foo
   foo
   bash-5.1$
   bash-5.1$