You'll find everything you need in jQuery's Getting Involved help page:
Filing Bugs and Building Test Cases
This is the best way to contribute to jQuery core. Please read through the full guide detailing How to Report Bugs.
Committing and Pull Requests
If you wish to contribute code to jQuery core please make sure you've first filed a bug report detailing your specific bug or feature request.
Next, create an account on Github (if you haven't done so already).
Create a fork of the jQuery Github project (More details of forking). More details concerning how to build jQuery can be found in the Downloading jQuery guide.
Before you write any code be sure to create a new branch in your repository in which all the changes will be committed. More details about Git branches can be found in the Pro Git chapter on branches and in the chapter on remote branches .
After your new branch has been pushed to your repository you can now send a pull request. Be sure to reference the bug(s) that you're fixing in the commit messages and in the pull request description (this helps us to track the changes easier).
We also have a number of Tips for jQuery Bug Patching detailing the exact commands that you need to run in order to properly contribute (and test).
The process seems rather typical of an open source project. The list of team members lists the jQuery board and core contributors, you can't expect everyone who ever committed a single line of code to the project to be listed there. I don't see what's concerning you with that list, every major open source project maintains some sort of lead/core contributors list.
Lastly, since your contribution is about a bug, make sure to search jQuery's issue tracker on whether the bug has already been reported, and if not, report it before doing anything else.