docs(angular.equals): fix simple typo

- JavasScript -> Javascript

Closes angular#4323

Author: mjtamlyn

src/Angular.js

@@ -705,7 +705,7 @@ function shallowCopy(src, dst) {
  *
  * * Both objects or values pass `===` comparison.
  * * Both objects or values are of the same type and all of their properties pass `===` comparison.
- * * Both values are NaN. (In JavasScript, NaN == NaN => false. But we consider two NaN as equal)
+ * * Both values are NaN. (In JavaScript, NaN == NaN => false. But we consider two NaN as equal)
  * * Both values represent the same regular expression (In JavasScript,
  *   /abc/ == /abc/ => false. But we consider two regular expressions as equal when their textual
  *   representation matches).