Modify README file for scripts with the necessary 9pfs documentation

Signed-off-by: Neagu Dragos-Ionut <dragosneagu28@gmail.com>

Author: NDragos

redis/scripts/README.md

@@ -54,3 +54,15 @@ e.g.
 ./scripts/run/fc.x86_64
 ./scripts/run/xen.arm64
 ```
+
+## Build and Run for <plat> / <arch> using a different file system  
+
+```console
+./scripts/run/<plat>.<arch>.<file_system>
+```
+
+e.g.
+
+```console
+./scripts/run/qemu.x86_64.9pfs
+```