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/srml/randomness-collective-flip/src/lib.rs

@@ -87,7 +87,7 @@ decl_storage! {
 		/// Series of block headers from the last 81 blocks that acts as random seed material. This
 		/// is arranged as a ring buffer with `block_number % 81` being the index into the `Vec` of
 		/// the oldest hash.
-		RandomMaterial get(random_material): Vec<T::Hash>;
+		RandomMaterial get(fn random_material): Vec<T::Hash>;
 	}
 }