patch 9.1.1338: Calling expand() interferes with cmdcomplete_info()

Problem:  Calling expand() interferes with cmdcomplete_info()
          (after 9.1.1329).
Solution: Only clear cmdline_orig when starting/ending cmdline mode
          (zeertzjq).

closes: #17192

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/cmdexpand.pro b/src/proto/cmdexpand.pro
index 73db378..92e9dcb 100644
--- a/src/proto/cmdexpand.pro
+++ b/src/proto/cmdexpand.pro
@@ -11,6 +11,7 @@
 char_u *ExpandOne(expand_T *xp, char_u *str, char_u *orig, int options, int mode);
 void ExpandInit(expand_T *xp);
 void ExpandCleanup(expand_T *xp);
+void clear_cmdline_orig(void);
 int showmatches(expand_T *xp, int wildmenu);
 char_u *addstar(char_u *fname, int len, int context);
 void set_expand_context(expand_T *xp);