xz: Update Authors list in a few files.

src/xz/args.c

@@ -5,7 +5,8 @@
 ///
 /// \note       Filter-specific options parsing is in options.c.
 //
-//  Author:     Lasse Collin
+//  Authors:    Lasse Collin
+//              Jia Tan
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.

src/xz/args.h

@@ -3,7 +3,8 @@
 /// \file       args.h
 /// \brief      Argument parsing
 //
-//  Author:     Lasse Collin
+//  Authors:    Lasse Collin
+//              Jia Tan
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.

src/xz/coder.c

@@ -3,7 +3,8 @@
 /// \file       coder.c
 /// \brief      Compresses or uncompresses a file
 //
-//  Author:     Lasse Collin
+//  Authors:    Lasse Collin
+//              Jia Tan
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.

src/xz/coder.h

@@ -3,7 +3,8 @@
 /// \file       coder.h
 /// \brief      Compresses or uncompresses a file
 //
-//  Author:     Lasse Collin
+//  Authors:    Lasse Collin
+//              Jia Tan
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.

src/xz/message.c

@@ -3,7 +3,8 @@
 /// \file       message.c
 /// \brief      Printing messages
 //
-//  Author:     Lasse Collin
+//  Authors:    Lasse Collin
+//              Jia Tan
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.