contributing: Don't link to project list with different names

The first paragraph links to the list of projects three times as:

* code repositories
* list of projects
* list of specific projects

This is confusing since a first time read does not see that he ends
up on the same page three times. So names things consistently and
drop the first link entirely.

Contributing.rst

@@ -3,9 +3,9 @@
 Contributing
 ============
 
-We welcome merge requests and issues being filed in our `code repositories <https://source.puri.sm/Librem5/>`_. Typically, issues get filed under the project that the issue relates to and you can browse our `list of projects <https://source.puri.sm/Librem5/>`_. For example, if you find an issue with the documentation, you can file an issue under the `developer docs <https://source.puri.sm/Librem5/developer.puri.sm/issues>`_ project. An issue can be any mistake you found in the project, e.g. a crash, a bug, or even a typo. You are welcome to file an issue when you want to make us aware of some important topic relating to the project as well.
+We welcome merge requests and issues being filed in our code repositories. Typically, issues get filed under the project that the issue relates to and you can browse our `list of projects <https://source.puri.sm/Librem5/>`_. For example, if you find an issue with the documentation, you can file an issue under the `developer docs <https://source.puri.sm/Librem5/developer.puri.sm/issues>`_ project. An issue can be any mistake you found in the project, e.g. a crash, a bug, or even a typo. You are welcome to file an issue when you want to make us aware of some important topic relating to the project as well.
 
-Aside from project specific issues, we do have an `Apps_issues <https://source.puri.sm/Librem5/Apps_Issues>`_ project to track tasks like applications to port to the phone or issues with them. Here you can add a task for a particular app to be ported to the phone. However, be sure to search our `list of specific projects <https://source.puri.sm/Librem5/>`_ first before opening an issue under `Apps_issues <https://source.puri.sm/Librem5/Apps_Issues>`_.
+Aside from project specific issues, we do have an `Apps_issues <https://source.puri.sm/Librem5/Apps_Issues>`_ project to track tasks like applications to port to the phone or issues with them. Here you can add a task for a particular app to be ported to the phone. However, be sure to search our `list of projects <https://source.puri.sm/Librem5/>`_ first before opening an issue under `Apps_issues <https://source.puri.sm/Librem5/Apps_Issues>`_.
 
 If you wish to own an issue, you will need additional permissions in our GitLab so please reach out in the community/librem-5 Matrix room and ask for a team member to grant you the "Reporter" role for the relevant project.