Godoc comment updates for default values
Godoc comment updates for default values

The `SetMode`, `SetSafe`, and `SetSocketTimeout` functions' documentation comments have been updated to show their default values.
deafgoat/mgo,Yottaa/mgo.v2,hexadecy/mgo,DroiTaipei/mgo,Yottaa/mgo.v2,Yottaa/mgo.v2,deafgoat/mgo,DroiTaipei/mgo,deafgoat/mgo,deafgoat/mgo,hexadecy/mgo,Yottaa/mgo.v2,hexadecy/mgo,DroiTaipei/mgo,hexadecy/mgo,DroiTaipei/mgo