docs: filesystems: Update code snippets in autofs.rst

Some of the struct definitions now have an autofs packet header.
Reflect these changes by adding a definition of this header and
place it wherever suitable.
Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/autofs.rst

@@ -322,8 +322,7 @@ notification messages to this pipe for the daemon to respond to.
 For version 5, the format of the message is::
 
 	struct autofs_v5_packet {
-		int proto_version;		/* Protocol version */
-		int type;			/* Type of packet */
+		struct autofs_packet_hdr hdr;
 		autofs_wqt_t wait_queue_token;
 		__u32 dev;
 		__u64 ino;
@@ -335,6 +334,13 @@ For version 5, the format of the message is::
 		char name[NAME_MAX+1];
         };
 
+And the format of the header is::
+
+	struct autofs_packet_hdr {
+		int proto_version;		/* Protocol version */
+		int type;			/* Type of packet */
+	};
+
 where the type is one of ::
 
 	autofs_ptype_missing_indirect
@@ -395,8 +401,7 @@ The available ioctl commands are:
 	anything suitable to expire.  A pointer to a packet::
 
 		struct autofs_packet_expire_multi {
-			int proto_version;		/* Protocol version */
-			int type;			/* Type of packet */
+			struct autofs_packet_hdr hdr;
 			autofs_wqt_t wait_queue_token;
 			int len;
 			char name[NAME_MAX+1];