fix(excmd): append original command to error message

Revert the change to do_cmdline_cmd() from #5226.

This function is used in many places, so making it different from Vim
leads to small differences from Vim in the behavior of some functions
like execute() and assert_fails(). If DOCMD_VERBOSE really needs to be
removed somewhere, a do_cmdline() call without DOCMD_VERBOSE is also
shorter than a do_cmdline() call with DOCMD_VERBOSE.

test/functional/lua/commands_spec.lua

@@ -214,7 +214,7 @@ describe(':luado command', function()
   end)
   it('fails in sandbox when needed', function()
     curbufmeths.set_lines(0, 1, false, {"ABC", "def", "gHi"})
-    eq('Vim(luado):E48: Not allowed in sandbox',
+    eq('Vim(luado):E48: Not allowed in sandbox: sandbox luado runs = (runs or 0) + 1',
        pcall_err(command, 'sandbox luado runs = (runs or 0) + 1'))
     eq(NIL, funcs.luaeval('runs'))
   end)