add file associations for ".c++" and ".h++" file extensions

[therloux]

i think vscode should map .c++ and .h++ file extensions to c++ by default. now, i know c++ is a language that has lots of file extensions associated with it, so it would make sense not doing it for all of them, but i'd argue .c++ and .h++ should be added because it would bring better compatibility with compilers, as some of them, like gcc, recognise them by default, and seti-ui, vscode's default file theme, also identifies them already. besides, i also propose making windows computers recognise those file extensions, and the only way for a user to do it is using the registry editor, which can be very dangerous if you don't really know what you're doing.

plus, there are thousands of files on github alone that have .c++ and .h++ as extensions (source) (i know that number is rather small compared to other files extensions, especially .cpp and .hpp, but it's still an expressive number that i don't think should be ignored.)

[therloux]

just to be clear, i know vscode already includes .c++ in file.associations out of the box -- i'm talking about including .h++ as well, and trating both of them as c++ files on windows. currently on windows you have to set .c++ and .h++ files to open on vscode, and the files don't have vscode's c++ icon, even when they're opened on vscode by default. (this doesn't happen to other file extensions like .cpp and .h/.hpp)