nsnake: add page (#4937)

pages/linux/nsnake.md

@@ -0,0 +1,24 @@
+# nsnake
+
+> Snake game in the terminal.
+> More information: <https://github.com/alexdantas/nsnake/>.
+
+- Start a snake game:
+
+`nsnake`
+
+- Navigate the snake:
+
+`{{Up|Down|Left|Right}} arrow key`
+
+- Pause/unpause the game:
+
+`p`
+
+- Quit the game:
+
+`q`
+
+- Show help during the game:
+
+`h`