Currently, ReactEventListener is a DOM-specific module but it has a generic sounding name that is confusing to contributors (i.e., confusing to me).

Let's rename it to ReactDOMEventListener. This should be pretty easy – just rename the file and update (and re-sort) the imports.

# @philipp-spiess is working on this task.
*       |           .               +--------+|SimpleEvent|
 *       |           .               |         |Plugin     |
 * +-----|------+    .               v         +-----------+
 * |     |      |    .    +--------------+                    +------------+
 * |     +-----------.--->|EventPluginHub|                    |    Event   |
 * |            |    .    |              |     +-----------+  | Propagators|
 * | ReactEvent |    .    |              |     |TapEvent   |  |------------|
 * |  Emitter   |    .    |              |<---+|Plugin     |  |other plugin|
 * |            |    .    |              |     +-----------+  |  utilities |
 * |     +-----------.--->|              |                    +------------+
 * |     |      |    .    +--------------+
 * +-----|------+    .                ^        +-----------+
 *       |           .                |        |Enter/Leave|
 *       +           .                +-------+|Plugin     |
 * +-------------+   .                         +-----------+
 * | application |   .
 * |-------------|   .
 * |             |   .
 * |             |   .
 * +-------------+   .
 *                   .
 *    React Core     .  General Purpose Event Plugin System
 */
var alreadyListeningTo = {};
var reactTopListenersCounter = 0;
/**
 * To ensure no conflicts with other potential React instances on the page
 */
var topListenersIDKey = '_reactListenersID' + ('' + Math.random()).slice(2);
function getListeningForDocument(mountAt) {