[cleanup][style] Remove comment for header guard #endif
We sometimes add a comment to the header guards
#endif // DUMUX_COMMON_BLA
I think this is unnecessary clutter and should be removed.
- The last
#endifin header files is always the header guard
- When copying a header file to create a new header it is easy to forget to change this comment
- When changing the header guard it is easy to forget to change this comment