patch 9.1.0563: Cannot process any Key event

Problem:  Cannot process any Key event
Solution: Add the KeyInputPre autocmd
          (Shougo Matsushita)

closes: #15182

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Co-authored-by: K.Takata <kentkt@csc.jp>
Signed-off-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 18cd2c1..eddafd0 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1995,7 +1995,8 @@
 					*v:char* *char-variable*
 v:char		Argument for evaluating 'formatexpr' and used for the typed
 		character when using <expr> in an abbreviation |:map-<expr>|.
-		It is also used by the |InsertCharPre| and |InsertEnter| events.
+		It is also used by the |InsertCharPre|, |InsertEnter| and
+		|KeyInputPre| events.
 
 			*v:charconvert_from* *charconvert_from-variable*
 v:charconvert_from