[Snek] [keith-packard/snek] 478382: Allow only one optional parameter to 'input'

[Keith Packard]

  Branch: refs/heads/one-input-param
  Home:   https://github.com/keith-packard/snek
  Commit: 47838293eeb5586712fffea5b50adaa4b39f5b55
      https://github.com/keith-packard/snek/commit/47838293eeb5586712fffea5b50adaa4b39f5b55
  Author: Keith Packard <keithp at keithp.com>
  Date:   2022-12-19 (Mon, 19 Dec 2022)

  Changed paths:
    M snek-input.c

  Log Message:
  -----------
  Allow only one optional parameter to 'input'

Python only allows zero or one parameters to the input function. Check
for more than one and emit an error.

Signed-off-by: Keith Packard <keithp at keithp.com>