vim-patch:8.2.2336: Vim9: not possible to extend dictionary with different type (#22425)

Problem:    Vim9: it is not possible to extend a dictionary with different
            item types.
Solution:   Add extendnew(). (closes vim/vim#7666)

b0e6b51364

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/eval.lua

@@ -120,6 +120,7 @@ return {
     expand={args={1, 3}, base=1},
     expandcmd={args={1, 2}, base=1},
     extend={args={2, 3}, base=1},
+    extendnew={args={2, 3}, base=1},
     feedkeys={args={1, 2}, base=1},
     file_readable={args=1, base=1, func='f_filereadable'},  -- obsolete
     filereadable={args=1, base=1, fast=true},