Rollup merge of #145238 - estebank:attr-overhaul, r=jdonszelmann

Tweak invalid builtin attribute output

 - Add link to reference/docs when possible
 - More accurate suggestions by supporting multiple alternative suggestions

```
error: malformed `crate_type` attribute input
  --> $DIR/crate-type-macro-call.rs:1:1
   |
LL | #![crate_type = foo!()]
   | ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
help: the following are the possible correct uses
   |
LL - #![crate_type = foo!()]
LL + #![crate_type = "bin"]
   |
LL - #![crate_type = foo!()]
LL + #![crate_type = "cdylib"]
   |
LL - #![crate_type = foo!()]
LL + #![crate_type = "dylib"]
   |
LL - #![crate_type = foo!()]
LL + #![crate_type = "lib"]
   |
   = and 4 other candidates
```

1 files changed, 24 insertions, 17 deletions

diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
index a7f8d3b9139..68ef6d6f32c 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_parse/src/validate_attr.rs
@@ -298,35 +298,42 @@ fn emit_malformed_attribute(
         suggestions.push(format!("#{inner}[{name}]"));
     }
     if let Some(descr) = template.list {
-        suggestions.push(format!("#{inner}[{name}({descr})]"));
+        for descr in descr {
+            suggestions.push(format!("#{inner}[{name}({descr})]"));
+        }
     }
     suggestions.extend(template.one_of.iter().map(|&word| format!("#{inner}[{name}({word})]")));
     if let Some(descr) = template.name_value_str {
-        suggestions.push(format!("#{inner}[{name} = \"{descr}\"]"));
+        for descr in descr {
+            suggestions.push(format!("#{inner}[{name} = \"{descr}\"]"));
+        }
     }
     if should_warn(name) {
         psess.buffer_lint(
             ILL_FORMED_ATTRIBUTE_INPUT,
             span,
             ast::CRATE_NODE_ID,
-            BuiltinLintDiag::IllFormedAttributeInput { suggestions: suggestions.clone() },
+            BuiltinLintDiag::IllFormedAttributeInput {
+                suggestions: suggestions.clone(),
+                docs: template.docs,
+            },
         );
     } else {
         suggestions.sort();
-        psess
-            .dcx()
-            .struct_span_err(span, error_msg)
-            .with_span_suggestions(
-                span,
-                if suggestions.len() == 1 {
-                    "must be of the form"
-                } else {
-                    "the following are the possible correct uses"
-                },
-                suggestions,
-                Applicability::HasPlaceholders,
-            )
-            .emit();
+        let mut err = psess.dcx().struct_span_err(span, error_msg).with_span_suggestions(
+            span,
+            if suggestions.len() == 1 {
+                "must be of the form"
+            } else {
+                "the following are the possible correct uses"
+            },
+            suggestions,
+            Applicability::HasPlaceholders,
+        );
+        if let Some(link) = template.docs {
+            err.note(format!("for more information, visit <{link}>"));
+        }
+        err.emit();
     }
 }