Hi Morgan,
I don't think the {{SP_Send_Alert_Info}} token is editable. I'm sure that you could always use the token in a custom field and append extra tokens next to it if this would be preferable.
Otherwise if you want to change it you could make your own snippet with the similar data the token contains:
- First name and last name as a link to the lead detail in Marketo
- A link to the lead in your CRM
- The campaign name in Marketo that sent the alert
- The time at which the alert was sent
Making your own using:
- Standard attribute tokens for name and link to lead detail with a lead ID token
- Link to your CRM with the correct ID token identifying the lead
- A trigger token for the campaign
- A system token for the date stamp
- Then change or add whatever you want
All depends what you want to edit, it seems doable! 
/Erik