Minor Updates of Documentation

Author: Teddy-van-Jerry

README.md

@@ -14,6 +14,14 @@ To use the package, run
 cargo add pytv
 ```
 
+## Features
+### Python Template
+This is the basic feature of this package.
+
+### Instantiation
+The crate feature `inst` is enabled by default.
+YAML contents between `<INST>` and `</INST>` are used to provide instantiation information.
+
 ## Related Auto Generator Projects
 - **FLAMES**: template-based C++ library for Vitis HLS
   [[website](https://flames.autohdw.com)]

src/inst.rs

@@ -2,6 +2,7 @@ use super::Convert;
 use std::error::Error;
 use std::io::Write;
 
+/// Represents the state of module instantiation.
 enum InstState {
     None,
     Begin,

src/lib.rs

@@ -1,7 +1,11 @@
 //! Python Templated Verilog
 //! 
 //! # Generation Process
-//! `.pytv` --> `.v.py` --> `.py`
+//! ```txt
+//! .pytv ----> .v.py --+-> .v
+//!                     |
+//!                     +-> .inst
+//! ```
 //! 
 //! # Examples
 //! To be added.