vim-patch:8.2.0861: cannot easily get all the current marks (#13676)

Problem:    Cannot easily get all the current marks.
Solution:   Add getmarklist(). (Yegappan Lakshmanan, closes #6032)
cfb4b47de0

Cherry-pick the column number fix from patch v8.2.0871
because patch v8.2.0871 cannot be fully ported
without the method patches.

Co-authored-by: Peter Wolf <pwolf2310@gmail.com>

src/nvim/eval.lua

@@ -150,6 +150,7 @@ return {
     getjumplist={args={0, 2}},
     getline={args={1, 2}},
     getloclist={args={1, 2}},
+    getmarklist={args={0, 1}},
     getmatches={args={0, 1}},
     getpid={},
     getpos={args=1},