docs(readme): fix headings

README.md

@@ -45,23 +45,23 @@
 </div>
 <br>
 
-## Overview
+# Overview
 
 The `sec-parser` project simplifies the process of extracting meaningful information from SEC EDGAR HTML documents. It organizes the document's source code into a list or tree of elements that correspond to the visual structure of the document. This includes distinct elements for section titles, paragraphs, and tables, making the data easier to analyze and understand. 
 
 This tool is especially beneficial for Artificial Intelligence (AI) and Large Language Models (LLM) applications. It significantly improves the efficiency of data extraction and analysis in these fields.
 
 [**Explore the Demo!**](https://sec-parser-output-visualizer.app.alphanome.dev/)
 
-## Installation
+# Installation
 
 You can install `sec-parser` using pip:
 
 ```bash
 pip install sec-parser
 ```
 
-## Usage
+# Usage
 
 ```python
 import sec_parser as sp