Add "[skip ci]" to MantisBT commit messages

Commits on TWN do not add any tags. It's up to the tool used to importing these translations into your GitHub project to request the export of data from TWN, format the file as needed, and upload the update to GitHub, using any convenient message in the import commit made **in GitHub** by the user controling that import and using his own account credentials for Git (or for any other external repository). User account and their rights are distinct, managed in separate realms (anyone can instantly read and export data at any time from TWN, but specific user accounts with appropriate rights are needed to import into your development repository).

Note that I do not reject or oppose your demand. This is just a suggestion that you can still use an an alternate solution, which would then not depend on changes to be made on this wiki by its local admins or developers, and that your project can manage itself (this wiki cannot manage usages made on external sites like GitHub, where translated messages will be uploaded and integrated at their own rate and in their own development and support branches).