Update %timeit documentation: replace best time with average time (#14141) This PR addresses outdated documentation for the `%timeit` magic command. As of version 6.0.0rc1, `%timeit` measures the average time instead of the best time. - Related PR at the time: https://github.com/ipython/ipython/pull/9984 However, the documentation still reflects the old behavior. ### 1. Description of the `-r` option The current documentation states the following: https://ipython.readthedocs.io/en/stable/interactive/magics.html#magic-timeit > -r<R>: number of repeats <R>, each consisting of <N> loops, and take the best result. Default: 7 This seems to be the correct `average result`. The actual code calculates the average: https://github.com/ipython/ipython/blob/f49a797f1488a3f54a0030de12d92393f878f335/IPython/core/magics/execution.py#L112-L119 ### 2. The format of the `%timeit` results in the sample code for `%alias_magic` is outdated. Current documentation: https://ipython.readthedocs.io/en/stable/interactive/magics.html#magic-alias_magic > In [2]: %t -n1 pass > 1 loops, best of 3: 954 ns per loop Actual result: > 107 ns ± 43.6 ns per loop (mean ± std. dev. of 7 runs, 1 loop each) The following pages also have outdated notation: - Overview: https://ipython.readthedocs.io/en/stable/overview.html#main-features-of-the-interactive-shell - Introducing Tutorial: https://ipython.readthedocs.io/en/stable/interactive/tutorial.html#magic-functions - IPython reference: https://ipython.readthedocs.io/en/stable/interactive/reference.html#magic-command-system - Python vs IPython: https://ipython.readthedocs.io/en/stable/interactive/python-ipython-diff.html#magics