Update README.md → Discord flair fixed

Author: Zeioth

README.md

@@ -5,7 +5,7 @@ Visualize your Markdown as mindmaps with markmap
 
 <div align="center">
   <a href="https://discord.gg/ymcMaSnq7d" rel="nofollow">
-    <img src="https://img.shields.io/discord/1121138836525813760?color=azure&labelColor=6DC2A4&logo=discord&logoColor=black&label=Join the discord server&style=for-the-badge" data-canonical-src="https://img.shields.io/discord/1121138836525813760">
+    <img src="https://img.shields.io/discord/1121138836525813760?color=azure&labelColor=6DC2A4&logo=discord&logoColor=black&label=Join%20the%20discord%20server&style=for-the-badge" alt="Discord">
   </a>
 </div>