Clarify removed controls in 3.1 and 5.0 (#4288)

* add info about removed controls

* .net core 5 -> .net 5

Co-authored-by: Igor Velikorossov <[email protected]>

Author: gewarren

xml/System.Windows.Forms/ContextMenu.xml

@@ -21,11 +21,16 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <summary>Represents a shortcut menu. Although <see cref="T:System.Windows.Forms.ContextMenuStrip" /> replaces and adds functionality to the <see cref="T:System.Windows.Forms.ContextMenu" /> control of previous versions, <see cref="T:System.Windows.Forms.ContextMenu" /> is retained for both backward compatibility and future use if you choose.</summary>
+    <summary>Represents a shortcut menu.
+    
+This class is not available in .NET Core 3.1 and later versions. Use <see cref="T:System.Windows.Forms.ContextMenuStrip" /> instead, which replaces and extends the <see cref="T:System.Windows.Forms.ContextMenu" /> control.</summary>
     <remarks>
       <format type="text/markdown"><![CDATA[  
   
-## Remarks  
+## Remarks
+
+This class is not available in .NET Core 3.1 and later versions. Use <see cref="T:System.Windows.Forms.ContextMenuStrip" /> instead.
+
  The <xref:System.Windows.Forms.ContextMenu> class represents shortcut menus that can be displayed when the user clicks the right mouse button over a control or area of the form. Shortcut menus are typically used to combine different menu items from a <xref:System.Windows.Forms.MainMenu> of a form that are useful for the user given the context of the application. For example, you can use a shortcut menu assigned to a <xref:System.Windows.Forms.TextBox> control to provide menu items for changing the font of the text, finding text within the control, or Clipboard features for copying and pasting text. You can also display new <xref:System.Windows.Forms.MenuItem> objects in a shortcut menu that are not located within a <xref:System.Windows.Forms.MainMenu> to provide situation specific commands that are not appropriate for the <xref:System.Windows.Forms.MainMenu> to display.  
   
  Typically, a shortcut menu is displayed when a user clicks the right mouse button over a control or the form itself. Visible controls and <xref:System.Windows.Forms.Form> have a <xref:System.Windows.Forms.Control.ContextMenu%2A> property that binds the <xref:System.Windows.Forms.ContextMenu> class to the control that displays the shortcut menu. More than one control can use a <xref:System.Windows.Forms.ContextMenu>. You can use the <xref:System.Windows.Forms.ContextMenu.SourceControl%2A> property to determine which control last displayed the shortcut menu in order to perform tasks specific to the control or to modify the shortcut menu displayed for the control.  

xml/System.Windows.Forms/DataGrid.xml

@@ -49,11 +49,16 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <summary>Displays ADO.NET data in a scrollable grid. The <see cref="T:System.Windows.Forms.DataGridView" /> control replaces and adds functionality to the <see cref="T:System.Windows.Forms.DataGrid" /> control; however, the <see cref="T:System.Windows.Forms.DataGrid" /> control is retained for both backward compatibility and future use, if you choose.</summary>
+    <summary>Displays ADO.NET data in a scrollable grid.
+    
+This class is not available in .NET Core 3.1 and later versions. Use the <see cref="T:System.Windows.Forms.DataGridView" /> control instead, which replaces and extends the <see cref="T:System.Windows.Forms.DataGrid" /> control.</summary>
     <remarks>
       <format type="text/markdown"><![CDATA[  
   
-## Remarks  
+## Remarks
+
+This class is not available in .NET Core 3.1 and later versions. Use the <see cref="T:System.Windows.Forms.DataGridView" /> control instead.
+
  The <xref:System.Windows.Forms.DataGrid?displayProperty=nameWithType> displays Web-like links to child tables. You can click on a link to navigate to the child table. When a child table is displayed, a back button appears in the caption that can be clicked to navigate back to the parent table. The data from the parent rows is displayed below the caption and above the column headers. You can hide the parent row information by clicking the button to the right of the back button.  
   
  To display a table in the <xref:System.Windows.Forms.DataGrid?displayProperty=nameWithType> at run time, use the <xref:System.Windows.Forms.DataGrid.SetDataBinding%2A> method to set the <xref:System.Windows.Forms.DataGrid.DataSource%2A> and <xref:System.Windows.Forms.DataGrid.DataMember%2A> properties to a valid data source. The following data sources are valid:  

xml/System.Windows.Forms/DataGridView.xml

@@ -21,11 +21,16 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <summary>Represents the menu structure of a form. Although <see cref="T:System.Windows.Forms.MenuStrip" /> replaces and adds functionality to the <see cref="T:System.Windows.Forms.MainMenu" /> control of previous versions, <see cref="T:System.Windows.Forms.MainMenu" /> is retained for both backward compatibility and future use if you choose.</summary>
+    <summary>Represents the menu structure of a form.
+    
+This class is not available in .NET Core 3.1 and later versions. Use <see cref="T:System.Windows.Forms.MenuStrip" /> instead, which replaces and extends the <see cref="T:System.Windows.Forms.MainMenu" /> control.</summary>
     <remarks>
       <format type="text/markdown"><![CDATA[  
   
-## Remarks  
+## Remarks
+
+This class is not available in .NET Core 3.1 and later versions. Use <see cref="T:System.Windows.Forms.MenuStrip" /> instead.
+
  The <xref:System.Windows.Forms.MainMenu> control represents the container for the menu structure of a form. A menu is composed of <xref:System.Windows.Forms.MenuItem> objects that represent the individual menu commands in the menu structure. Each <xref:System.Windows.Forms.MenuItem> can be a command for your application or a parent menu for other submenu items. To bind the <xref:System.Windows.Forms.MainMenu> to the <xref:System.Windows.Forms.Form> that will display it, assign the <xref:System.Windows.Forms.MainMenu> to the <xref:System.Windows.Forms.Form.Menu%2A> property of the <xref:System.Windows.Forms.Form>.  
   
  For applications that will have support for multiple languages, you can use the <xref:System.Windows.Forms.MainMenu.RightToLeft%2A> property to display the text of the menu from right to left to support languages such as Arabic.