docs(of): add of operator docs (#3907)
docs(of): add of operator docs (#3907)

* docs(of): add of operator docs

add description and examples for the rxjs/of observable creator

none

* docs(of-operator): convert generic values param in docs to multiple

use spread indicator to indicate in of operator docs that it accepts multiple comma separated
arguments

none

* docs(of-operator): re-arrange docs for correct jsdoc rendering

the added documentation has been moved below the overloads so it can be rendered correctly on the
docs page

none

ReactiveX/rxjs,ReactiveX/rxjs,ReactiveX/RxJS,Brocco/RxJS,Brocco/RxJS,martinsik/rxjs,benlesh/RxJS,martinsik/rxjs,kwonoj/RxJS,trxcllnt/RxJS,ReactiveX/RxJS,ReactiveX/RxJS,martinsik/rxjs,kwonoj/RxJS,Brocco/RxJS,ReactiveX/rxjs,kwonoj/RxJS,benlesh/RxJS,trxcllnt/RxJS,trxcllnt/RxJS,ReactiveX/rxjs,benlesh/RxJS,ReactiveX/RxJS,martinsik/rxjs,benlesh/RxJS,trxcllnt/RxJS,Brocco/RxJS,kwonoj/RxJS