add win+d shortcut

Author: HyperNova114

CheatSheets/windows-cheatsheet.md

@@ -46,6 +46,7 @@
 | `Win + E` | Open File Explorer |
 | `Win + ,` | see your desktop until you hold keys |
 | `Win + v` | to see clipboard and emoji |
+| `Win + d` | to display and hide the desktop |
 
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