Merge #256

256: Update c-with-rust.md r=adamgreig a=lukeyeager

Add the `--use-core` flag for folks using the bindgen binary

Co-authored-by: Luke Yeager <lukeyeager@users.noreply.github.com>

Author: bors[bot]

src/interoperability/c-with-rust.md

@@ -84,7 +84,7 @@ Rather than manually generating these interfaces, which may be tedious and error
 2. Write a `bindings.h` file, which `#include "..."`'s each of the files you gathered in step one
 3. Feed this `bindings.h` file, along with any compilation flags used to compile
   your code into `bindgen`. Tip: use `Builder.ctypes_prefix("cty")` /
-  `--ctypes-prefix=cty` and `Builder.use_core()` to make the generated code `#![no_std]` compatible.
+  `--ctypes-prefix=cty` and `Builder.use_core()` / `--use-core` to make the generated code `#![no_std]` compatible.
 4. `bindgen` will produce the generated Rust code to the output of the terminal window. This file may be piped to a file in your project, such as `bindings.rs`. You may use this file in your Rust project to interact with C/C++ code compiled and linked as an external library. Tip: don't forget to use the [`cty`](https://crates.io/crates/cty) crate if your types in the generated bindings are prefixed with `cty`.
 
 [bindgen]: https://github.com/rust-lang/rust-bindgen