It would be convenient to have "Suggest a change" link in the bottom of
documentation pages to allow people propose fixes and additions. 

This can be a simple feedback form with an optional "patch" field that
submits mail to a list or simply adds documentation comment.

More complex approach would be construct patch right in the browser.
Then add it for review into "documentation queue". "documentation queue"
is a part of documentation system to automatically submit patches after
review (and optionally incrementally-recompile existing output formats).
In case of page comments review status can be displayed in place
together with comments and patches. The whole edit/review process may
require single sign on system described in issue #2837