[Pharo-project] Added issue 3351: Comments in MIMEDocument erroneously refer to MIMEObject

Pharo image: Pharo Pharo core version: 1.1-11411 Virtual machine used: n/a Class browser used (if applicable): n/a In the following method, comments refer to MIMEObject (which I assume is an earlier name for MIMEDocument): MIMEDocument class>>#contentType:content I realize this is a small thing, but it did cause me to hunt around for MIMEObject for a while.