In my opinion these trivial changes should be submitted as text in a bug report rather than patches or pull requests. For brevity a regex statement like s/foo/baz/ can be used.
That's a way one could do things, and fairly common with non-GitHub repositories. But it's not the cultural norm on GitHub. The typical process is to submit pull requests even for small doc changes. The interface encourages this by even having an "edit" button and online editor, which wraps up the fork/commit/pull-request cycle into a button push. And the GitHub docs encourage that as well.
I think any serious projects should have a CLA, or require sign off like the Linux project does, and suggesting a change is the only way to get around having to deal with that.
For known contributors, yeah, it's a nice feature.