Add a first pass at jsdoc.

[##130415655] #596

src/core/matchers/toContain.js

@@ -1,4 +1,13 @@
 getJasmineRequireObj().toContain = function() {
+  /**
+   * {@link expect} the actual value to contain a specific value.
+   * @function
+   * @name matchers#toContain
+   * @param {Object} expected - The value to look for.
+   * @example
+   * expect(array).toContain(anElement);
+   * expect(string).toContain(substring);
+   */
   function toContain(util, customEqualityTesters) {
     customEqualityTesters = customEqualityTesters || [];