"": output previous action to stderr

When redirecting output from "", it prints the command
to stdout, which garbles things like:

	% foo
	<inspect output>
	% "" > /dev/snarf

Now, we send it to stderr.

rc/bin/""

@@ -4,10 +4,10 @@ PROMPT='[^ 	]*(%|;)+[ 	]+'
 
 _x = `{" $* | tail -1}
 if(~ $#_x 0) {
-	echo no such command found
+	echo no such command found >[1=2]
 	exit notfound
 }
 
-echo '	' $_x
+echo '	' $_x >[1=2]
 _x=`{ echo -n 'eval '''; echo $_x | sed 's/^'$PROMPT'//; s/''/''''/g; s/$/''/'}
 rc -c $"_x