Detect when attribute is provided by missing `derive` macro

```
error: cannot find attribute `empty_helper` in this scope
  --> $DIR/derive-helper-legacy-limits.rs:17:3
   |
LL | #[empty_helper]
   |   ^^^^^^^^^^^^
   |
help: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
   |
LL + #[derive(Empty)]
LL | struct S2;
   |
```

Look at proc-macro attributes when encountering unknown attribute

```
error: cannot find attribute `sede` in this scope
  --> src/main.rs:18:7
   |
18 |     #[sede(untagged)]
   |       ^^^^
   |
help: the derive macros `Serialize` and `Deserialize` accept the similarly named `serde` attribute
   |
18 |     #[serde(untagged)]
   |       ~~~~~

error: cannot find attribute `serde` in this scope
  --> src/main.rs:12:7
   |
12 |     #[serde(untagged)]
   |       ^^^^^
   |
   = note: `serde` is in scope, but it is a crate, not an attribute
help: `serde` is an attribute that can be used by the derive macros `Serialize` and `Deserialize`, you might be missing a `derive` attribute
   |
10 | #[derive(Serialize, Deserialize)]
   |
```

3 files changed, 14 insertions, 0 deletions

diff --git a/tests/ui/proc-macro/derive-helper-legacy-limits.stderr b/tests/ui/proc-macro/derive-helper-legacy-limits.stderr
index f5cd455435d..df3c5c47ddb 100644
--- a/tests/ui/proc-macro/derive-helper-legacy-limits.stderr
+++ b/tests/ui/proc-macro/derive-helper-legacy-limits.stderr
@@ -3,6 +3,12 @@ error: cannot find attribute `empty_helper` in this scope
    |
 LL | #[empty_helper]
    |   ^^^^^^^^^^^^
+   |
+help: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
+   |
+LL + #[derive(Empty)]
+LL | struct S2;
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/proc-macro/derive-helper-shadowing.stderr b/tests/ui/proc-macro/derive-helper-shadowing.stderr
index f284b1c54dd..1206778bb23 100644
--- a/tests/ui/proc-macro/derive-helper-shadowing.stderr
+++ b/tests/ui/proc-macro/derive-helper-shadowing.stderr
@@ -16,6 +16,7 @@ error: cannot find attribute `empty_helper` in this scope
 LL |             #[derive(GenHelperUse)]
    |                      ^^^^^^^^^^^^
    |
+   = note: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
    = note: this error originates in the derive macro `GenHelperUse` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider importing this attribute macro through its public re-export
    |
@@ -31,6 +32,7 @@ LL |         #[empty_helper]
 LL |             gen_helper_use!();
    |             ----------------- in this macro invocation
    |
+   = note: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
    = note: this error originates in the macro `gen_helper_use` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider importing this attribute macro through its public re-export
    |
diff --git a/tests/ui/proc-macro/disappearing-resolution.stderr b/tests/ui/proc-macro/disappearing-resolution.stderr
index 734e0cd2ab6..6c0f1a52915 100644
--- a/tests/ui/proc-macro/disappearing-resolution.stderr
+++ b/tests/ui/proc-macro/disappearing-resolution.stderr
@@ -3,6 +3,12 @@ error: cannot find attribute `empty_helper` in this scope
    |
 LL | #[empty_helper]
    |   ^^^^^^^^^^^^
+   |
+help: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
+   |
+LL + #[derive(Empty)]
+LL | struct S;
+   |
 
 error[E0603]: derive macro import `Empty` is private
   --> $DIR/disappearing-resolution.rs:11:8