Issue #10405: Document IDLE context menus in Standard Library document

and IDLE Help file.  (Thanks to Nick ODell and Todd Rovito for suggestions.)
Update Debug menu options in docs to match current code plus various other
minor IDLE doc and help edits.

Doc/library/idle.rst

@@ -154,27 +154,56 @@ The rest of this menu lists the names of all open windows; select one to bring
 it to the foreground (deiconifying it if necessary).
 
 
-Debug menu (in the Python Shell window only)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Debug menu
+^^^^^^^^^^
+
+* in the Python Shell window only
 
 Go to file/line
-   look around the insert point for a filename and linenumber, open the file, and
-   show the line.
+   Look around the insert point for a filename and line number, open the file,
+   and show the line.  Useful to view the source lines referenced in an
+   exception traceback.
 
-Open stack viewer
-   show the stack traceback of the last exception
+Debugger
+   Run commands in the shell under the debugger.
 
-Debugger toggle
-   Run commands in the shell under the debugger
+Stack viewer
+   Show the stack traceback of the last exception.
 
-JIT Stack viewer toggle
-   Open stack viewer on traceback
+Auto-open Stack Viewer
+   Open stack viewer on traceback.
 
 .. index::
    single: stack viewer
    single: debugger
 
 
+Edit context menu
+^^^^^^^^^^^^^^^^^
+
+* Right-click in Edit window (Control-click on OS X)
+
+Set Breakpoint
+   Sets a breakpoint.  Breakpoints are only enabled when the debugger is open.
+
+Clear Breakpoint
+   Clears the breakpoint on that line.
+
+.. index::
+   single: Set Breakpoint
+   single: Clear Breakpoint
+   single: breakpoints
+
+
+Shell context menu
+^^^^^^^^^^^^^^^^^^
+
+* Right-click in Python Shell window (Control-click on OS X)
+
+Go to file/line
+   Same as in Debug menu.
+
+
 Basic editing and navigation
 ----------------------------
 

Lib/idlelib/help.txt

@@ -80,7 +80,7 @@ Shell Menu (only in Shell window):
 Debug Menu (only in Shell window):
 
 	Go to File/Line   -- look around the insert point for a filename
-		             and linenumber, open the file, and show the line
+		             and line number, open the file, and show the line
 	Debugger (toggle) -- Run commands in the shell under the debugger
 	Stack Viewer      -- Show the stack traceback of the last exception
 	Auto-open Stack Viewer (toggle) -- Open stack viewer on traceback
@@ -92,7 +92,7 @@ Options Menu:
                           Startup Preferences may be set, and Additional Help
                           Sources can be specified.
 			  
-			  On MacOS X this menu is not present, use
+			  On OS X this menu is not present, use
 			  menu 'IDLE -> Preferences...' instead.
 	---
 	Code Context --	  Open a pane at the top of the edit window which
@@ -120,6 +120,15 @@ Help Menu:
 	---
 	(Additional Help Sources may be added here)
 
+Edit context menu (Right-click / Control-click in Edit window):
+
+	Set Breakpoint   -- Sets a breakpoint (when debugger open)
+	Clear Breakpoint -- Clears the breakpoint on that line
+
+Shell context menu (Right-click / Control-click in Shell window):
+
+	Go to file/line -- Same as in Debug menu
+
 
 ** TIPS **
 ==========
@@ -222,7 +231,7 @@ Python Shell window:
 
 	Alt-p retrieves previous command matching what you have typed.
 	Alt-n retrieves next.
-	      (These are Control-p, Control-n on the Mac)
+	      (These are Control-p, Control-n on OS X)
 	Return while cursor is on a previous command retrieves that command.
 	Expand word is also useful to reduce typing.