Add link to contribute.jabref.org (#3748)
Add link to contribute.jabref.org (#3748)

* Add link to contribute.jabref.org

* Changed link text

* Rewrote sentence

Siedlerchr/jabref,tobiasdiez/jabref,Siedlerchr/jabref,JabRef/jabref,zellerdev/jabref,sauliusg/jabref,sauliusg/jabref,tobiasdiez/jabref,sauliusg/jabref,sauliusg/jabref,zellerdev/jabref,JabRef/jabref,JabRef/jabref,Siedlerchr/jabref,Siedlerchr/jabref,zellerdev/jabref,tobiasdiez/jabref,JabRef/jabref,zellerdev/jabref,tobiasdiez/jabref,zellerdev/jabref