add documentation link badge

Author: lukepistrol

README.md

@@ -10,6 +10,9 @@
   <a aria-label="Join the community on Discord" href="https://discord.gg/vChUXVf9Em" target="_blank">
     <img alt="" src="https://img.shields.io/badge/Join%20the%20community-black.svg?style=for-the-badge&logo=Discord">
   </a>
+  <a aria-label="Read the Documentation" href="https://codeeditapp.github.io/CodeEditTextView/documentation/codeedittextview/" target="_blank">
+    <img alt="" src="https://img.shields.io/badge/Documentation-black.svg?style=for-the-badge&logo=readthedocs&logoColor=blue">
+  </a>
 </p>
 
 An Xcode-inspired code editor view written in Swift powered by tree-sitter for [CodeEdit](https://github.com/CodeEditApp/CodeEdit). Features include syntax highlighting (based on the provided theme), code completion, find and replace, text diff, validation, current line highlighting, minimap, inline messages (warnings and errors), bracket matching, and more.