Fix typo on vaporwave-3d-scene-with-threejs.mdx (#648)

Deleted an extra letter.

content/vaporwave-3d-scene-with-threejs.mdx

@@ -546,7 +546,7 @@ The Linear WebGL scene actually leverages some **Three.js post-processing effect
 What's post-processing in the world of Three.js?
 It's a way to apply graphical effects to your scene. In our case, the RGBShift is one specific effect among many others.
 
-I encourage you to check out or just skim through the dedicated doc on [how to use prost-processing](https://threejs.org/docs/?q=post#manual/en/introduction/How-to-use-post-processing) before continuing.
+I encourage you to check out or just skim through the dedicated doc on [how to use post-processing](https://threejs.org/docs/?q=post#manual/en/introduction/How-to-use-post-processing) before continuing.
 
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