nvim: Fix path completing on insert mode return

When hitting return in insert mode we would enter a path completion.
With this change the completion is moved from <c-m> (i.e. return) to
<c-t>.

nvim/.config/nvim/lua/plugins/pickers.lua

@@ -207,8 +207,8 @@ return { -- file/item pickers and managers
 				end,
 				desc = "path complete",
 			},
-			{ -- TODO: Does it work reliably in various circumstances?
-				"<c-m>",
+			{
+				"<c-t>",
 				function()
 					require("fzf-lua").complete_path()
 				end,