Update Process.xml (#3844)

* Update Process.xml

Added clarification about MainWindowTitle on Unix, with respect to dotnet/runtime#31658

* Update xml/System.Diagnostics/Process.xml

Co-Authored-By: Stephen Toub <[email protected]>

* Update xml/System.Diagnostics/Process.xml

Co-Authored-By: Dan Moseley <[email protected]>

Co-authored-by: Stephen Toub <[email protected]>
Co-authored-by: Dan Moseley <[email protected]>

Author: 3 people

xml/System.Diagnostics/Process.xml

@@ -2501,7 +2501,9 @@ The calling process is a member of the associated process' descendant tree.</exc
           <format type="text/markdown"><![CDATA[  
 
 ## Remarks  
- A process has a main window associated with it only if the process has a graphical interface. If the associated process does not have a main window (so that <xref:System.Diagnostics.Process.MainWindowHandle%2A> is zero), <xref:System.Diagnostics.Process.MainWindowTitle%2A> is an empty string (""). If you have just started a process and want to use its main window title, consider using the <xref:System.Diagnostics.Process.WaitForInputIdle%2A> method to allow the process to finish starting, ensuring that the main window handle has been created. Otherwise, the system throws an exception.  
+ A process has a main window associated with it only if the process has a graphical interface. If the associated process does not have a main window (so that <xref:System.Diagnostics.Process.MainWindowHandle%2A> is zero), or if the system can't determine that there's a main window (such as may be the case on some Unix platforms), <xref:System.Diagnostics.Process.MainWindowTitle%2A> is an empty string ("").
+ 
+ If you have just started a process and want to use its main window title, consider using the <xref:System.Diagnostics.Process.WaitForInputIdle%2A> method to allow the process to finish starting, ensuring that the main window handle has been created. Otherwise, the system throws an exception.  
 
 > [!NOTE]
 >  The main window is the window that currently has the focus; note that this might not be the primary window for the process. You must use the <xref:System.Diagnostics.Process.Refresh%2A> method to refresh the <xref:System.Diagnostics.Process> object to get the current main window handle if it has changed.