patch 8.2.2958: function list test fails

Problem:    Function list test fails.
Solution:   Add newly added function to the list.  Fix typo.
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index f34891a..0d66d2b 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -952,6 +952,7 @@
 	browsedir()		put up a directory requester
 	confirm()		let the user make a choice
 	getchar()		get a character from the user
+	getcharstr()		get a character from the user as a string
 	getcharmod()		get modifiers for the last typed character
 	getmousepos()		get last known mouse position
 	echoraw()		output characters as-is