Bad documentation of dim

[Oleksandr]

There is nothing about the (-infinity)-dimension returned as -1 on the dim's documentation: ​http://www.singular.uni-kl.de/Manual/latest/sing_193.htm#SEC233

Would be nice to add the following example:

> dim(std(1)); 
-1

and explain the convention.

[hannes]

fixed. Remark: please do not use Manual/latest, but Manual/3-1-2 links: these should be more stable