📝 Match variable names

[ci skip]

docs/api/screen.md

@@ -15,11 +15,11 @@ An example of creating a window that fills the whole screen:
 ```javascript
 const {app, BrowserWindow, screen: electronScreen} = require('electron');
 
-let mainWindow;
+let win;
 
 app.on('ready', () => {
   const {width, height} = electronScreen.getPrimaryDisplay().workAreaSize;
-  mainWindow = new BrowserWindow({width, height});
+  win = new BrowserWindow({width, height});
 });
 ```
 
@@ -28,7 +28,7 @@ Another example of creating a window in the external display:
 ```javascript
 const {app, BrowserWindow, screen: electronScreen} = require('electron');
 
-let mainWindow;
+let win;
 
 app.on('ready', () => {
   let displays = electronScreen.getAllDisplays();
@@ -41,7 +41,7 @@ app.on('ready', () => {
   }
 
   if (externalDisplay) {
-    mainWindow = new BrowserWindow({
+    win = new BrowserWindow({
       x: externalDisplay.bounds.x + 50,
       y: externalDisplay.bounds.y + 50
     });

docs/api/web-contents.md

@@ -700,8 +700,8 @@ Adds the specified path to DevTools workspace. Must be used after DevTools
 creation:
 
 ```javascript
-mainWindow.webContents.on('devtools-opened', () => {
-  mainWindow.webContents.addWorkSpace(__dirname);
+win.webContents.on('devtools-opened', () => {
+  win.webContents.addWorkSpace(__dirname);
 });
 ```
 
@@ -763,13 +763,13 @@ An example of sending messages from the main process to the renderer process:
 
 ```javascript
 // In the main process.
-let mainWindow = null;
+let win = null;
 
 app.on('ready', () => {
-  mainWindow = new BrowserWindow({width: 800, height: 600});
-  mainWindow.loadURL(`file://${__dirname}/index.html`);
-  mainWindow.webContents.on('did-finish-load', () => {
-    mainWindow.webContents.send('ping', 'whoooooooh!');
+  win = new BrowserWindow({width: 800, height: 600});
+  win.loadURL(`file://${__dirname}/index.html`);
+  win.webContents.on('did-finish-load', () => {
+    win.webContents.send('ping', 'whoooooooh!');
   });
 });
 ```