vim-patch:8.2.2468: not easy to get the full command name from a shortened one

Problem:    Not easy to get the full command name from a shortened one.
Solution:   Add fullcommand(). (Martin Tournoij, closes vim/vim#7777)
038e09ee76

src/nvim/eval.lua

@@ -133,6 +133,7 @@ return {
     foldtext={},
     foldtextresult={args=1, base=1},
     foreground={},
+    fullcommand={args=1, base=1},
     funcref={args={1, 3}, base=1},
     ['function']={args={1, 3}, base=1},
     garbagecollect={args={0, 1}},