patch 9.1.1151: too many strlen() calls in getchar.c

Problem:  too many strlen() calls in getchar.c
Solution: store last inserted and recorded lengths,
          add functions to retrieve those and use those
          functions (John Marriott)

closes: #16720

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/getchar.pro b/src/proto/getchar.pro
index 1473879..d1d78a2 100644
--- a/src/proto/getchar.pro
+++ b/src/proto/getchar.pro
@@ -1,6 +1,8 @@
 /* getchar.c */
 char_u *get_recorded(void);
+size_t get_recorded_len(void);
 char_u *get_inserted(void);
+size_t get_inserted_len(void);
 int stuff_empty(void);
 int readbuf1_empty(void);
 void typeahead_noflush(int c);