Update clang-format file

[nmm0]

What Needs to be Done?

• Fix clang-format identing of preprocessor directives
• Make clang-format negatively indent access specifiers

[jstrzebonski]

@nmm0

Nic, for access modifiers AccessModifierOffset needs to be changed to -2.

About the preprocessor directives indention, what style is correct? Take a look at paragraph IndentPPDirectives here: https://clang.llvm.org/docs/ClangFormatStyleOptions.html, basically:

None:

#if FOO
#if BAR
#include <foo>
#endif
#endif

AfterHash:

#if FOO
#  if BAR
#    include <foo>
#  endif
#endif

BeforeHash:

#if FOO
  #if BAR
    #include <foo>
  #endif
#endif

Currently we have BeforeHash.