chore: register -> on & on:spec:file:preprocessor -> file:preprocessor

Author: chrisbreiding

README.md

@@ -17,8 +17,8 @@ In your project's [plugins file](https://on.cypress.io/guides/guides/plugins.htm
 ```javascript
 const webpack = require('@cypress/webpack-preprocessor')
 
-module.exports = (register, config) => {
-  register('on:spec:file:preprocessor', webpack(config))
+module.exports = (on, config) => {
+  on('file:preprocessor', webpack(config))
 }
 ```
 
@@ -28,15 +28,15 @@ Pass in options as the second argument to `webpack`:
 
 ```javascript
 const webpack = require('@cypress/webpack-preprocessor')
-module.exports = (register, config) => {
+module.exports = (on, config) => {
   const options = {
     // send in the options from your webpack.config.js, so it works the same
     // as your app's code
     webpackOptions: require('../../webpack.config'),
     watchOptions: {},
   }
 
-  register('on:spec:file:preprocessor', webpack(config, options))
+  on('file:preprocessor', webpack(config, options))
 }
 ```
 
@@ -83,11 +83,11 @@ If, for example, you want to update the options for the `babel-loader` to add th
 ```javascript
 const webpack = require('@cypress/webpack-preprocessor')
 
-module.exports = (register, config) => {
+module.exports = (on, config) => {
   const options = webpack.defaultOptions
   options.webpackOptions.module.rules[0].use.options.presets.push('babel-preset-stage-3')
 
-  register('on:spec:file:preprocessor', webpack(config, options))
+  on('file:preprocessor', webpack(config, options))
 }
 ```
 

index.js

@@ -33,7 +33,7 @@ const defaultOptions = {
 // export a function that returns another function, making it easy for users
 // to configure like so:
 //
-// register('on:spec:file:preprocessor', webpack(config, userOptions))
+// on('file:preprocessor', webpack(config, userOptions))
 //
 const preprocessor = (config, userOptions = {}) => {
   if (!config || typeof config.isTextTerminal !== 'boolean') {
@@ -44,7 +44,7 @@ const preprocessor = (config, userOptions = {}) => {
 
 
   // we return function that accepts the arguments provided by
-  // the event 'on:spec:file:preprocessor'
+  // the event 'file:preprocessor'
   //
   // this function will get called for the support file when a project is loaded
   // (if the support file is not disabled)