Fix incorrect remarks in GCHandle.Free (#9848)

Fixes #4909

Author: reflectronic

xml/System.Runtime.InteropServices/GCHandle.xml

@@ -705,7 +705,7 @@
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- Use this property when using <xref:System.Runtime.InteropServices.GCHandleType.Weak> handles to determine if the <xref:System.Runtime.InteropServices.GCHandle> is still available. When the garbage collector collects the object, the <xref:System.Runtime.InteropServices.GCHandleType.Weak> handle can still be resurrected in the finalizer. In that case, the handle is not allocated (it is lost when the garbage collector attempts to collect the object), even though the target object is valid.  
+ If <xref:System.Runtime.InteropServices.GCHandle.Free> was called on this <xref:System.Runtime.InteropServices.GCHandle>, or if this <xref:System.Runtime.InteropServices.GCHandle> is not initialized, the handle is not allocated and this property returns `false`.
   
  ]]></format>
         </remarks>