Merge fa6680ff76 into 38016cb2d6

> Yes, you are right, if you just clone the repository and try to edit the exercises, the language server will not work. This is one downside of the current approach. But this only affects developing exercises.
>
> The new method of doing Rustlings is to install Rustlings using `cargo install rustlings` (not published yet), then running `rustlings init`. No repo cloning happens. Instead, the directory `rustlings/` will be created where you find the exercises. The language server works there out of the box :)
>
> I need to add a warning when people try to work on the exercises from the repository. Thanks pointing this out.
>
> -- @mo8it, https://github.com/rust-lang/rustlings/issues/1935#issuecomment-2067664066

Other references:

 - Previous `rustlings lsp` command: https://github.com/rust-lang/rustlings/pull/1026
 - The changelog says "LSP support out of the box", https://github.com/rust-lang/rustlings/blob/main/CHANGELOG.md#lsp-support-out-of-the-box

README.md

@@ -45,6 +45,18 @@ cargo install rustlings
 
 </details>
 
+> [!CAUTION]
+> Don't try to clone the repository to do the exercises! `rust-analyzer` won't work in that case. Please follow the instructions above instead.
+> 
+> <details>
+> <summary>Why?</summary>
+>
+>The intended way to run Rustlings is to install the binary and run `rustlings init` as described in the installation/initialization sections. This generates a `Cargo.toml` (different than what you see in the repository) that includes each exercise as a separate binary target which is enough for `rust-analyzer` to work.
+>
+>If you just clone the repository and try to run and edit the exercises directly, the language server will not work.
+>
+> </details>
+
 ### Initialization
 
 After installing Rustlings, run the following command to initialize the `rustlings/` directory:

exercises/22_clippy/clippy3.rs

@@ -4,9 +4,11 @@
 #[rustfmt::skip]
 #[allow(unused_variables, unused_assignments)]
 fn main() {
-    let my_option: Option<()> = None;
+    let my_option: Option<&str> = None;
+    // Assume that you don't know the value of `my_option`.
+    // In the case of `Some`, we want to print its value.
     if my_option.is_none() {
-        println!("{:?}", my_option.unwrap());
+        println!("{}", my_option.unwrap());
     }
 
     let my_arr = &[

solutions/22_clippy/clippy3.rs

@@ -3,11 +3,11 @@ use std::mem;
 #[rustfmt::skip]
 #[allow(unused_variables, unused_assignments)]
 fn main() {
-    let my_option: Option<()> = None;
+    let my_option: Option<&str> = None;
     // `unwrap` of an `Option` after checking if it is `None` will panic.
     // Use `if-let` instead.
     if let Some(value) = my_option {
-        println!("{value:?}");
+        println!("{value}");
     }
 
     // A comma was missing.