pindef.h issuie

[guannan-he]

In "pindef.h", line35, comment says "USB-CDC (Takes PA8,PA9,PA10,PA11)".
However, PA8 was connected to J9 and uses as relay2, PA9 and PA10 were defined as serial1, which connects to J27.
Therefore, the commenting may be "USB-CDC (Takes PA11, PA12)"
"scales calibration.cpp" also has this problem.

Sorry for propose a new issue instead of committing a git. Still pretty confused about how git works.