docs: Notice in @typegpu/three guide about WebGL incompatibility (#2060)

Author: iwoplaza

apps/typegpu-docs/src/content/docs/ecosystem/typegpu-three/index.mdx

@@ -15,6 +15,12 @@ with a focus on composability, intuitive sharing of logic across modules and cus
 
 You can see a [direct comparison between TSL and TypeGPU here](#differences-between-tsl-and-typegpu).
 
+:::caution
+If your end user's device doesn't support WebGPU, Three.js enables a WebGL fallback. Currently, using @typegpu/three
+makes your app only work on WebGPU-enabled devices. If you need WebGL support, [bombard this issue with reactions
+and state your use case in the comments.](https://github.com/software-mansion/TypeGPU/issues/1637)
+:::
+
 ## Setup
 
 import { Tabs, TabItem } from '@astrojs/starlight/components';