Oops, forgot the [1]
However, it being for build commands [1], or default extension, etc., I'm not sure having one single "C and C++ headers and sources" is a great idea.
[1] I mostly agree stock build commands are seldom (if ever) useful with C and C++, but for the most basic "Hello World". .o generation is even less useful. However, I do have a custom script (that fetches some deps by inspecting includes) there I use to build very simple or test stuff, and it's very handy in such cases. But in all cases, we could imagine having many sorts of commands, maybe a linter or anything; anyway not necessarily the same handling both C and C++.