Improve Header file lang detection by taking into consideration C++ exclusive extensions

[AbbasNS]

To deduce a header file language (C vs C++), we currently look at:

• vcxproj global setting in Visual Studio mode.
• The language of an equivalent entry from the compilation database in CMake project mode.

While this method works most of the time, its accuracy can be improved when the header file extension is known to be used exclusively in C++: .hh,.hpp,.hxx,.h++,.ipp

Proposal: Take into consideration the header file language while filling HeaderFileLanguage.

Note: We should enforce that the equivalent entry in CMake project mode has a file with a C++ extension to not end up with Cpp language with C compilation options.

Related community thread: https://community.sonarsource.com/t/sonarlint-c-wrong-language-for-header-files/99263