patch 8.0.1497: getting the jump list requires parsing the output of :jumps

Problem:    Getting the jump list requires parsing the output of :jumps.
Solution:   Add getjumplist(). (Yegappan Lakshmanan, closes #2609)
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 837418b..590fde4 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -807,6 +807,7 @@
 	getbufinfo()		get a list with buffer information
 	gettabinfo()		get a list with tab page information
 	getwininfo()		get a list with window information
+	getjumplist()		get a list of jump list entries
 
 Command line:					*command-line-functions*
 	getcmdline()		get the current command line