Fix broken link on resolving conflicts (#13748)

link was broken because it had an "." at the end. Closes #13746

(cherry picked from commit b103a1d)

CONTRIBUTING.rst

@@ -1356,7 +1356,7 @@ as "apache" so you can refer to it easily:
    You can configure different merge tools with it. You can also use IntelliJ/PyCharm's excellent merge tool.
    When you open a project in PyCharm which has conflicts, you can go to VCS > Git > Resolve Conflicts and there
    you have a very intuitive and helpful merge tool. For more information, see
-   `Resolve conflicts <https://www.jetbrains.com/help/idea/resolving-conflicts.html.>`_.
+   `Resolve conflicts <https://www.jetbrains.com/help/idea/resolving-conflicts.html>`_.
 
 8. After you've solved your conflict run: