vim-patch:9.0.0234: cannot make difference between :normal end and argument char (#19879)

Problem:    Cannot make difference between the end of :normal and a character
            in its argument.
Solution:   Add the "typebuf_was_empty" flag. (closes vim/vim#10950)
8d69637133

src/nvim/getchar.c

@@ -2400,7 +2400,8 @@ static int vgetorpeek(bool advance)
   vgetc_busy++;
 
   if (advance) {
-    KeyStuffed = FALSE;
+    KeyStuffed = false;
+    typebuf_was_empty = false;
   }
 
   init_typebuf();
@@ -2626,6 +2627,11 @@ static int vgetorpeek(bool advance)
           }
           tc = c;
 
+          // set a flag to indicate this wasn't a normal char
+          if (advance) {
+            typebuf_was_empty = true;
+          }
+
           // return 0 in normal_check()
           if (pending_exmode_active) {
             exmode_active = true;