[ISSUE #17]Add doc for cheetah_string mod

src/lib.rs

@@ -1,5 +1,23 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
+//! No more relying solely on the standard library's String! CheetahString is a versatile string type that can store static strings, dynamic strings, and byte arrays.
+//! It is usable in both `std` and `no_std` environments. Additionally, CheetahString supports serde for serialization and deserialization.
+//! CheetahString also supports the `bytes` feature, allowing conversion to the `bytes::Bytes` type.
+//! This reduces memory allocations during cloning, enhancing performance.
+//! example:
+//! ```rust
+//! use cheetah_string::CheetahString;
+//!
+//!
+//!  let s = CheetahString::from("Hello, world!");
+//!
+//!  let s2:&'static str = "Hello, world!";
+//!  let s3 = CheetahString::from_static_str(s2);
+//!
+//!  let s4 = CheetahString::new();
+//!
+//! ```
+//!
 mod cheetah_string;
 
 #[cfg(feature = "serde")]