Match tag line on github in README to downplay implied reliability of binding to C++

Author: fitzgen

README.md

@@ -2,7 +2,7 @@
 
 [`impl period`](https://blog.rust-lang.org/2017/09/18/impl-future-for-rust.html) has been started! Join us at [Gitter.im](https://gitter.im/rust-impl-period/WG-dev-tools-bindgen).
 
-**`bindgen` automatically generates Rust FFI bindings to C and C++ libraries.**
+**`bindgen` automatically generates Rust FFI bindings to C (and some C++) libraries.**
 
 For example, given the C header `doggo.h`: