Add @since to most JSDoc comments

- See jasmine/jasmine.github.io#117

src/core/matchers/toBePositiveInfinity.js

@@ -3,6 +3,7 @@ getJasmineRequireObj().toBePositiveInfinity = function(j$) {
    * {@link expect} the actual value to be `Infinity` (infinity).
    * @function
    * @name matchers#toBePositiveInfinity
+   * @since 2.6.0
    * @example
    * expect(thing).toBePositiveInfinity();
    */