feat(cmp): add opts_extend to make it easier for user to change mapping, sources, etc.

lua/lazyvim/plugins/coding.lua

@@ -19,6 +19,7 @@ return {
     --   auto_brackets = { "python" }
     -- }
     -- ```
+    opts_extend = { "mapping", "experimental", "completion", "formatting", "sources" },
     opts = function()
       vim.api.nvim_set_hl(0, "CmpGhostText", { link = "Comment", default = true })
       local cmp = require("cmp")