Include note [4] about %f, i.e. that it can be used to parse milliseconds

[RichardBradley]

It is not immediately clear from the description of "%f", "Microsecond as a decimal number, zero-padded on the left", that it can be used to parse millisecond fields.

It is safe to use for parsing millisecond fields, as explained in note [4] in the docs: "When used with the strptime() method, the %f directive accepts from one to six digits and zero pads on the right."

As you can see from e.g. https://stackoverflow.com/questions/698223/how-can-i-parse-a-time-string-containing-milliseconds-in-it-with-python and this comment: https://stackoverflow.com/questions/698223/how-can-i-parse-a-time-string-containing-milliseconds-in-it-with-python#comment46200797_698279 this is confusing.

It might help people in the future to get note [4] included in this page?

I can't see an easy way to do that in your build.py, so I haven't created a PR for you, sorry.