📝 Match variable names

[ci skip]

docs/tutorial/quick-start.md

@@ -88,24 +88,24 @@ const {BrowserWindow} = electron;
 
 // Keep a global reference of the window object, if you don't, the window will
 // be closed automatically when the JavaScript object is garbage collected.
-let mainWindow;
+let win;
 
 function createWindow() {
   // Create the browser window.
-  mainWindow = new BrowserWindow({width: 800, height: 600});
+  win = new BrowserWindow({width: 800, height: 600});
 
   // and load the index.html of the app.
-  mainWindow.loadURL(`file://${__dirname}/index.html`);
+  win.loadURL(`file://${__dirname}/index.html`);
 
   // Open the DevTools.
-  mainWindow.webContents.openDevTools();
+  win.webContents.openDevTools();
 
   // Emitted when the window is closed.
-  mainWindow.on('closed', () => {
+  win.on('closed', () => {
     // Dereference the window object, usually you would store windows
     // in an array if your app supports multi windows, this is the time
     // when you should delete the corresponding element.
-    mainWindow = null;
+    win = null;
   });
 }
 
@@ -126,7 +126,7 @@ app.on('window-all-closed', () => {
 app.on('activate', () => {
   // On OS X it's common to re-create a window in the app when the
   // dock icon is clicked and there are no other windows open.
-  if (mainWindow === null) {
+  if (win === null) {
     createWindow();
   }
 });

docs/tutorial/using-pepper-flash-plugin.md

@@ -29,14 +29,14 @@ app.commandLine.appendSwitch('ppapi-flash-path', '/path/to/libpepflashplayer.so'
 app.commandLine.appendSwitch('ppapi-flash-version', '17.0.0.169');
 
 app.on('ready', () => {
-  mainWindow = new BrowserWindow({
+  win = new BrowserWindow({
     width: 800,
     height: 600,
     webPreferences: {
       plugins: true
     }
   });
-  mainWindow.loadURL(`file://${__dirname}/index.html`);
+  win.loadURL(`file://${__dirname}/index.html`);
   // Something else
 });
 ```

docs/tutorial/using-widevine-cdm-plugin.md

@@ -59,9 +59,9 @@ app.commandLine.appendSwitch('widevine-cdm-path', '/path/to/widevinecdmadapter.p
 // The version of plugin can be got from `chrome://plugins` page in Chrome.
 app.commandLine.appendSwitch('widevine-cdm-version', '1.4.8.866');
 
-let mainWindow = null;
+let win = null;
 app.on('ready', () => {
-  mainWindow = new BrowserWindow({
+  win = new BrowserWindow({
     webPreferences: {
       // The `plugins` have to be enabled.
       plugins: true