Should we use parenthesis for printing in vignettes

[TimTaylor]

In the new vignettes I've currently used the pattern (dat <- mtcars) to both assign and print within a single line. This is a little unusual so we may want to change. See comment reference below:

I think it should boil down to what most users are familiar with. I am quite possiby just old-fashioned, but I have not seen it used as a new default (I think?), so maybe best just type the name of the object we want to print?

Originally posted by @thibautjombart in #91 (comment)

[TimTaylor]

parenthesis printing now removed