ENH: Generate doctest log

[Sheila-nk]

• added a generate_log function to document functions whose doctest examples are executed

I installed this branch of scpdt to scipy to see what the log would look like. I have attached it below.

doctest.log

[ev-br]

Probably want to output full names of functions/methods:

scipy.stats._continuous_distns ============================== _digammainv
fit
betaprime_gen
fit fit fit fit fit fit fit fit fit fit

is less useful otherwise.

[Sheila-nk]

Current log looks like this: doctest.log

[ev-br]

Let's close this. In the end of the day using --collect-only turned out to be simpler. Thanks Sheila!