fix presubmit stanza in the guidelines
fix presubmit stanza in the guidelines

cesarghali/keytransparency,gdbelvin/keytransparency,gdbelvin/keytransparency,google/keytransparency,alsophian/keytransparency,alsophian/keytransparency,google/keytransparency,AMarcedone/keytransparency,AMarcedone/keytransparency,cesarghali/keytransparency