If you're being picky, then I can be picky too: the concept of a "pull request" isn't defined in that manpage, only the command "request-pull" is. A "pull request" is an entity in itself.
The command may exist within git, but it's not a part of most people's git workflows. "Pull Request" is a term that's far more commonly attributed-to and associated with tools like GitHub, Gitlab, Bitbucket etc.
Did you know that git has the ability to send patches via email, built in [1]? Git has a lot of functions that the majority of people don't use.
[1] https://git-scm.com/docs/git-send-email