Add changed send trigger to list of changes in IDE 2.x Serial Monitor

In the Arduino IDE 1.x Serial Monitor, sending is triggered via the "Send" button or by pressing the "Enter" key.

There is no "Send" button in the Arduino IDE 2.x Serial Monitor.

The keyboard trigger was changed from "Enter" to "Ctrl + Enter". This is explained to the user by placeholder text in
the input field, but that text disappears as soon as they click on the field, so it is easy to miss that information.
Feedback from users indicates this is the case.

For this reason, it will be important to clearly document the change.

Author: per1234

content/software/ide-v2/tutorials/ide-v2-serial-monitor/ide-v2-serial-monitor.md

@@ -44,6 +44,10 @@ A major advantage with having the Serial Monitor integrated with the editor is t
 
 You will find an example with more information on how to use this feature, further down this tutorial under the **Using multiple Serial Monitors simultaneously** section.
 
+### Different Send Trigger
+
+In the Arduino IDE 1.x Serial Monitor, data can be sent to the board by entering it in the field at the top of the window and then clicking the **Send** button or pressing the <kbd>**Enter**</kbd> key. In the Arduino IDE 2.0 Serial Monitor you must instead use the <kbd>**Ctrl**</kbd>+<kbd>**Enter**</kbd> keyboard shortcut (<kbd>**Command**</kbd>+<kbd>**Enter**</kbd> for macOS users).
+
 ## Using the Serial Monitor Tool
 
 The Serial Monitor tool is a really great tool for debugging and establishing communication between a computer and an Arduino. To use it is really easy, but there are some things that we need to do first.