Repository: clap-rs/clap (rust)

Issue:
Broken link in `default_values_t` error message
### Please complete the following tasks

- [X] I have searched the [discussions](https://github.com/clap-rs/clap/discussions)
- [X] I have searched the [open](https://github.com/clap-rs/clap/issues) and [rejected](https://github.com/clap-rs/clap/issues?q=is%3Aissue+label%3AS-wont-fix+is%3Aclosed) issues

### Rust Version

rustc 1.83.0 (90b35a623 2024-11-26)

### Clap Version

v4.5.23

### Minimal reproducible code

```
#[clap(default_values_t = Some(Vec::new()))]
foo: Option<Vec<String>>,
```

### Steps to reproduce the bug with the above code

```bash
cargo build
```

### Actual Behaviour

```text
error: #[arg(default_values_t)] can be used only on Vec types
       
       = note: see https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes
```

Link is a 404.

> The master branch of clap does not contain the path examples/derive_ref/README.md.

This link is repeated several times in https://github.com/clap-rs/clap/blob/fde45f9aea766fb8de46e3d46e6575f393c3b6b9/clap_derive/src/item.rs.

### Expected Behaviour

A working link.

### Additional Context

_No response_

### Debug Output

_No response_

Pull request description:
fix(derive): Update link for derive attributes
Fixes #5842

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Patch:
diff --git a/clap_derive/src/item.rs b/clap_derive/src/item.rs
index e48b200f..ab32918e 100644
--- a/clap_derive/src/item.rs
+++ b/clap_derive/src/item.rs
@@ -561,7 +561,7 @@ impl Item {
                             only on field level\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     };
 
                     let val = if let Some(expr) = &attr.value {
@@ -611,7 +611,7 @@ impl Item {
                             only on field level\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     };
                     let expr = attr.value_or_abort()?;
 
@@ -622,7 +622,7 @@ impl Item {
                             "#[arg(default_values_t)] can be used only on Vec types\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     }
                     let inner_type = inner_type(ty);
 
@@ -689,7 +689,7 @@ impl Item {
                             only on field level\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     };
 
                     let val = if let Some(expr) = &attr.value {
@@ -739,7 +739,7 @@ impl Item {
                             only on field level\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     };
                     let expr = attr.value_or_abort()?;
 
@@ -750,7 +750,7 @@ impl Item {
                             "#[arg(default_values_os_t)] can be used only on Vec types\n\n= note: {note}\n\n",
 
                             note = "see \
-                                https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes")
+                                https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes")
                     }
                     let inner_type = inner_type(ty);
 


Test patch:
diff --git a/tests/derive_ui/default_values_t_invalid.stderr b/tests/derive_ui/default_values_t_invalid.stderr
index 78a33696..0a6df929 100644
--- a/tests/derive_ui/default_values_t_invalid.stderr
+++ b/tests/derive_ui/default_values_t_invalid.stderr
@@ -1,6 +1,6 @@
 error: #[arg(default_values_t)] can be used only on Vec types
 
-       = note: see https://github.com/clap-rs/clap/blob/master/examples/derive_ref/README.md#magic-attributes
+       = note: see https://docs.rs/clap/latest/clap/_derive/index.html#arg-attributes
 
  --> tests/derive_ui/default_values_t_invalid.rs:6:11
   |