doc/md: fixed wrong sample code for gorm guide

changed doc to match atlas-provider-gorm repo

doc/md: fixed formatting

doc/md/guides/orms/gorm.md

@@ -129,7 +129,7 @@ import (
 )
 
 func main() {
-    stmts, err := gormschema.New("mysql", &models.User{}, &models.Pet{}).Load()
+    stmts, err := gormschema.New("mysql").Load(&models.User{}, &models.Pet{})
     if err != nil {
         fmt.Fprintf(os.Stderr, "failed to load gorm schema: %v\n", err)
         os.Exit(1)