vim-patch:9.0.1956: Custom completion skips orig cmdline if it invokes glob() (#25427)

Problem:  Custom cmdline completion skips original cmdline when pressing
          Ctrl-P at first match if completion function invokes glob().
Solution: Move orig_save into struct expand_T.

closes: vim/vim#13216

28a23602e8

src/nvim/ex_cmds_defs.h

@@ -245,6 +245,7 @@ struct expand {
   int xp_numfiles;              // number of files found by file name completion
   int xp_col;                   // cursor position in line
   int xp_selected;              // selected index in completion
+  char *xp_orig;                // originally expanded string
   char **xp_files;              // list of files
   char *xp_line;                // text being completed
 #define EXPAND_BUF_LEN 256