ChannelStaticErrorRate and ErrorErasure should print their intervals in str, repr and latex

[Johan Rosenkilde]

Number of errors/erasures added can be specified precisely or using an interval for these channels.

If constructing one of the channels with such an interval, e.g. (1,10), currently, the repr etc. functions print e.g.

 Static error rate channel creating 7 errors

It should, of course, read something like

 Static error rate channel creating between 1 and 10 errors

Similar for ErrorErasureChannel.

[Johan Rosenkilde]

Sorry, this is already fixed for StaticErrorRate. But not for ErrorErasure.

Btw. several tests in test_channel.sheet currently fail

[Johan Rosenkilde]

Oh yeah, and ErrorErasure currently prints "Static error rate channel ..." where it should be something like "Error-and-erasure channel ...".

[David Lucas]

Yup, I thought the same while writing the docstrings, and this change is propaged everywhere now. Failed copy-pasted print for ErrorErasure is now fixed.