Auto merge of #56770 - satyarohith:patch-1, r=Centril

docs(rustc): make hello() public

Running the example code [here](https://doc.rust-lang.org/rustc/what-is-rustc.html#basic-usage) throws error:
```
error[E0603]: function `hello` is private
 --> src/main.rs:4:10
  |
4 |     foo::hello();
  |          ^^^^^
```
Making  `hello()` public fixes the problem.

Author: bors

src/doc/rustc/src/what-is-rustc.md

@@ -50,7 +50,7 @@ fn main() {
 And a `foo.rs` that had this:
 
 ```rust,ignore
-fn hello() {
+pub fn hello() {
     println!("Hello, world!");
 }
 ```
@@ -65,4 +65,4 @@ No need to tell `rustc` about `foo.rs`; the `mod` statements give it
 everything that it needs. This is different than how you would use a C
 compiler, where you invoke the compiler on each file, and then link
 everything together. In other words, the *crate* is a translation unit, not a
-particular module.
+particular module.