Rollup merge of rust-lang#82211 - henryboisdequin:make-setup-msgs-better, r=jyn514

make `suggest_setup` help messages better

When I first built the compiler and didn't create a `config.toml.example`, the following was emitted:

```
help: consider running `x.py setup` or copying `config.toml.example`
```

I ran `x.py setup` but got an error so in this PR I made the help messages a little clearer.

Author: JohnTitor

src/bootstrap/bin/main.rs

@@ -22,7 +22,10 @@ fn main() {
     let suggest_setup = !config.config.exists() && !matches!(config.cmd, Subcommand::Setup { .. });
     if suggest_setup {
         println!("warning: you have not made a `config.toml`");
-        println!("help: consider running `x.py setup` or copying `config.toml.example`");
+        println!(
+            "help: consider running `./x.py setup` or copying `config.toml.example` by running \
+            `cp config.toml.example config.toml`"
+        );
     } else if let Some(suggestion) = &changelog_suggestion {
         println!("{}", suggestion);
     }
@@ -31,7 +34,10 @@ fn main() {
 
     if suggest_setup {
         println!("warning: you have not made a `config.toml`");
-        println!("help: consider running `x.py setup` or copying `config.toml.example`");
+        println!(
+            "help: consider running `./x.py setup` or copying `config.toml.example` by running \
+            `cp config.toml.example config.toml`"
+        );
     } else if let Some(suggestion) = &changelog_suggestion {
         println!("{}", suggestion);
     }