Fix incorrect string escaping in OS.shell_open() method Windows path example

Corrected improper string escaping in the OS.shell_open() Windows path example. Backslashes are now properly escaped to prevent string parsing errors. Also, added a new alternative example of how to mount a Windows path with OS.shell_open().

doc/classes/OS.xml

@@ -809,7 +809,8 @@
 			<param index="0" name="uri" type="String" />
 			<description>
 				Requests the OS to open a resource identified by [param uri] with the most appropriate program. For example:
-				- [code]OS.shell_open("C:\\Users\name\Downloads")[/code] on Windows opens the file explorer at the user's Downloads folder.
+				- [code]OS.shell_open("C:\\Users\\name\\Downloads")[/code] on Windows opens the file explorer at the user's Downloads folder.
+				- [code]OS.shell_open("C:/Users/name/Downloads")[/code] also works on Windows and opens the file explorer at the user's Downloads folder.
 				- [code]OS.shell_open("https://godotengine.org")[/code] opens the default web browser on the official Godot website.
 				- [code]OS.shell_open("mailto:[email protected]")[/code] opens the default email client with the "To" field set to [code][email protected][/code]. See [url=https://datatracker.ietf.org/doc/html/rfc2368]RFC 2368 - The [code]mailto[/code] URL scheme[/url] for a list of fields that can be added.
 				Use [method ProjectSettings.globalize_path] to convert a [code]res://[/code] or [code]user://[/code] project path into a system path for use with this method.