hclpack: Fix name range for unsupported attribute

Fixes an issue where the name range may be incorrect in case there are
multiple attributes and one of them is wrong. Another attribute's name
range could overwrite the previous one as the attr variable is
overwritten in the for loop.

hclpack/structure.go

@@ -101,11 +101,12 @@ func (b *Body) content(schema *hcl.BodySchema, remain *Body) (*hcl.BodyContent,
 				}
 			}
 		}
+
 		diags = append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,
 			Summary:  "Unsupported argument",
 			Detail:   fmt.Sprintf("An argument named %q is not expected here.%s", name, suggestion),
-			Subject:  &attr.NameRange,
+			Subject:  attr.NameRange.Ptr(),
 		})
 	}