update jsdocs for createConnection

[lineus]

per my comment on #6756 this change removes the old parameter signature from the createConnection jsdoc example.

I'm also thinking we could change line 420 in connection.js from

  if (options) {

to

  if (options && typeof options === 'object') {

but I'm not sure if we should throw an error instead if options isn't an object? @vkarpov15, what do you think?

all tests pass.

[vkarpov15]

We should throw an error if options isn't an object. Cleaner developer experience that way because people might stumble across the old syntax like the poster of #6756 did. Feel free to put in a PR for that.

[vkarpov15]

Thanks!