analysis option of biblioNetwork() function need more description

[jooyoungseo]

I really appreciate @massimoaria for always promptly addressing all the issues.

The responsiveness makes me more like this package, and it really helps my academic work.

I was wondering if you could also address the following at your easiest convenience.

It would be so much appreciated if you could provide more information on biblioNetwork() function arguments in its help document.

For instance, analysis argument can have any of the four character objects (i.e., "collaboration", "coupling", "co-occurrences" or "co-citation"); however, I am so confused since no definitions of these concepts are missing while those seem very similar to each other. Would you mind adding brief definitions of each option to the user help document? Of course, users could examine bibliometrix package source code to understand the underlying calculation; however, it would be very helpful for users because they do not need to do reverse-engineering for this.

Many thanks again!