Maybe my understanding is wrong, but closure (and closurescript) are compiled languages. Angular is a UI framework, so comparing them is apples to oranges.
And I think the Angular community would be thrilled if it had even close to the kind of documentation that Rails has. You are correct, no one framework will rule them all, but there are examples of OS projects that have good docs (like jQuery and Rails) that can be used as comparisons when evaluating a framework.
You may be thinking of Clojure and ClojureScript — with a J. It's confusing naming, but those are different, and are not Google products.
In this thread, we're talking about Google's Closure (with an S) Library. Google also makes a Closure (with an S) Compiler, but it's more of an optimizer — it "compiles" from JavaScript to optimized JavaScript.
I would prefer to clear the confusion by calling Closure templates "soy templates", and differentiate it from the Closure compiler (for compiling javascript).
And I think the Angular community would be thrilled if it had even close to the kind of documentation that Rails has. You are correct, no one framework will rule them all, but there are examples of OS projects that have good docs (like jQuery and Rails) that can be used as comparisons when evaluating a framework.