doc/md: fixed wrong sample code for gorm guide

[kylelmh]

Background

https://atlasgo.io/guides/orms/gorm has the following sample code:

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

However, the syntax for gormschema.New only takes String as argument and the provided code would not compile.

Fix

Changed sample code contents to match https://github.com/ariga/atlas-provider-gorm README

[giautm]

Hey @kylelmh, thank you for submitting the fix. Can you please revert the change for styling and keep the fix only?

[kylelmh]

@giautm
Thanks for the comment. I have updated the md so that only one line is affected

[giautm]

thank you for your contribution.