ipython/ipython — pull request #6482 by jhamrick (2014-09-16 06:53:13+00:00)
Title: Clear prompt numbers in ClearOutput preprocessor

When choosing to clear all output in the notebook interface, it also clears all the prompt numbers. However, the `ClearOutput` preprocess does not currently clear prompt numbers -- only the outputs themselves. It seems like the behavior in these two places should be consistent, so this pull request modifies the `ClearOutput` preprocessor to also clear prompt numbers.