docs: Add doc_cfg in lib.rs to fix compilation on docsrs

sylvia/src/lib.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(docsrs, feature(doc_cfg))]
 //! Framework for creating CosmWasm Smart Contract with high-level abstraction layer
 //!
 //! Most of implementation lies in `sylvia-derive` crate which is reexported here

sylvia/src/multitest.rs

@@ -1,6 +1,6 @@
 //! This module provides utilities to work with `cw_multi_test` crate.
 //!
-//! Example usage:
+//! ## Example usage:
 //! ```rust
 //! # use sylvia::cw_std::{Response, StdResult};
 //! # use sylvia::types::{ExecCtx, InstantiateCtx, QueryCtx};