Remove 'formerly mcc' from the renamed metrics

[Nereboss]

After deciding to no longer rename the sonar complexity to mcc, we added 'formerly mcc' to it to give users some time to adapt to this big change.

This issue serves as a reminder to remove it in a couple of weeks (probably around end of may).

[Nereboss]

There are two places in the code where the translation happens as well as two tests where it needed to be adjusted. Searching for "formerly" in the codebase shows them. Both translation lines can be removed completely and in the tests the 'formerly mcc should be removed'.