cmd: document Rosa OS programs

The earlyinit and mbf program are not covered by the compatibility promise, so specify that here.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/sharefs/main.go

@@ -1,3 +1,10 @@
+// The sharefs FUSE filesystem is a permissionless shared filesystem.
+//
+// This filesystem is the primary means of file sharing between hakurei
+// application containers. It serves the same purpose in Rosa OS as /sdcard
+// does in AOSP.
+//
+// See help message for all available options.
 package main
 
 import (