Rollup merge of #25585 - sferik:change-default-gender, r=steveklabnik

Rollup merge of #25585 - sferik:change-default-gender, r=steveklabnik

The paper from which this example was taken made the mistake of assuming that all five philosophers are men. This it is a hypothetical example—there are no actual philosophers eating :spaghetti:—so there is no good reason to make this assumption. Since women make up about half of the human population, all things being equal, women should represent about half of the philosophers. However, because this mistake has stood since 1985, I have changed *all* of the pronouns to be female, to make up for lost time. If someone would like to revert this patch or switch to neutral pronouns after 30 years, feel free to set your alarm clock for 2045.

r? @steveklabnik, since this is a documentation change and was created after reading http://words.steveklabnik.com/ouroboros, where I noticed this mistake.