update: match DioxusLabs/docs#3

docs/reference/src/platforms/index.md

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+# Platforms
+
+Dioxus supports many different platforms. Below are a list of guides that walk you through setting up Dioxus for a specific platform.
+
+### Setup Guides
+- [Web](web.md)
+- [Server Side Rendering](ssr.md)
+- [Desktop](desktop.md)
+- [Mobile](mobile.md)
+- [TUI](tui.md)