vim-patch:8.2.0924: cannot save and restore a register properly

Problem:    Cannot save and restore a register properly.
Solution:   Add getreginfo() and make setreg() accept a dictionary. (Andy
            Massimino, closes vim/vim#3370)
bb861e293e

Cherry-pick eval.txt changes for getreginfo() from:
6aa57295cf
207f009326

src/nvim/eval.lua

@@ -166,6 +166,7 @@ return {
     getpos={args=1},
     getqflist={args={0, 1}},
     getreg={args={0, 3}},
+    getreginfo={args={0, 1}, base=1},
     getregtype={args={0, 1}},
     gettabinfo={args={0, 1}},
     gettabvar={args={2, 3}},