save_modified_file optionally add header information to source files

    This command will prompt you to update the header information.  
    The header generated will display the filename, the author name and
    the date of creation.  If the author block already exists then you
    will be prompted for an update comment and a comment line will be
    added to a comment block (this will be added if it doesn't exist).

    The file types which will cause a prompt are .c .h .e and .y suffix
    files.  All other files are saved as normal.
        
    A buffer specific variable used by this command is author-name 
    which allows an 80 character name used in the author block.
        
    The author and comment blocks are created at the beginning of the
    file.

