This "C/C++" bad habit is very commonly used, around Rust, to slyly imply there is no effective difference, but in a way that permits an injured response to criticism that "it just means C or C++". But it doesn't, unless you are talking about object file symbols or compiler optimizers; and often enough not then. What it does is encourage sloppy thinking, and resultant falsehoods. These falsehoods show up in the article, revealed if you change "C/C++" to "C or C++" in each case.
In several places, it says just "C++" yet is clearly still talking about C. It is OK not to know C++, or not like it. But things are hard enough without active falsehoods. It is not hard to get it right: if you are talking about C, write "C". That will always be correct. If you are talking about C++, say "C++".
Rust stands or falls on its own. It doesn't need invidious editorializing.