PsychoPy is an open-source, community-driven project. It is written and provided free out of goodwill by people that make no money from it and have other jobs to do. The way that open-source projects work is that users contribute back some of their time.
It has taken, literally, thousands of hours of programming to get PsychoPy where it is today and it is provided absolutely for free. Without someone working on it full time (which would mean charging you for it) the only way for the software to keep getting better is if people contribute back to the project.
Please, please, please make the effort to give a little back to this project. If you found the documentation hard to understand then think about how you would have preferred it to be written and contribute it.
For simple changes, and for users that aren’t so confident with things like version control systems then just send your changes to the mailing list.
If you want to make more substantial changes then it’s often good to discuss them first on the developers mailing list.
The ideal model, is to contribute via the repository on github. There is more information on that in the For Developers section of the documentation.
The easiest way to help the project is to write to the forum (mailing list) with suggestions and solutions.
For documentation suggestions please try to provide actual replacement text. You, as a user, are probably better placed to write this than the actual developers (they know too much to write good docs)!
If you had problems and worked out how to fix things, even if it turned out the problem was your own lack of understanding, please still contribute the information. Others are likely to have similar problems. Maybe the documentation could be clearer, or your email to the forum will be found by others googling for the same problem.