move doc

Author: burrbull

src/generate/register.rs

@@ -158,15 +158,15 @@ pub fn render(
         pub struct #_name_pc;
     });
 
-    let doc = format!("`read()` method returns [{0}::R]({0}::R) reader structure", &name_sc);
     if can_read {
+        let doc = format!("`read()` method returns [{0}::R]({0}::R) reader structure", &name_sc);
         out.push(quote! {
             #[doc = #doc]
             impl crate::Readable for #name_pc {}
         });
     }
-    let doc = format!("`write(|w| ..)` method takes [{0}::W]({0}::W) writer structure", &name_sc);
     if can_write {
+        let doc = format!("`write(|w| ..)` method takes [{0}::W]({0}::W) writer structure", &name_sc);
         out.push(quote! {
             #[doc = #doc]
             impl crate::Writable for #name_pc {}