Explicitly declare decl_storage! getters as functions (#3870)

* parse decl_storage getters with fn keyword

* test for get in decl_storage

* update all decl_storage! getters

* bump version

* adjust missed doc line

substrate/node-template/runtime/src/template.rs

@@ -24,8 +24,8 @@ decl_storage! {
 	trait Store for Module<T: Trait> as TemplateModule {
 		// Just a dummy storage item.
 		// Here we are declaring a StorageValue, `Something` as a Option<u32>
-		// `get(something)` is the default getter which returns either the stored `u32` or `None` if nothing stored
-		Something get(something): Option<u32>;
+		// `get(fn something)` is the default getter which returns either the stored `u32` or `None` if nothing stored
+		Something get(fn something): Option<u32>;
 	}
 }