[3.6] Fix typos in multiple `.rst` files (GH-1668) (#1702)

(cherry picked from commit 3378b2062c7fbb77a9b5e6d315d6b94160fac69a)
diff --git a/Doc/library/cmd.rst b/Doc/library/cmd.rst
index f40cfdf..3b4a8ff 100644
--- a/Doc/library/cmd.rst
+++ b/Doc/library/cmd.rst
@@ -266,10 +266,10 @@
             'Draw circle with given radius an options extent and steps:  CIRCLE 50'
             circle(*parse(arg))
         def do_position(self, arg):
-            'Print the current turle position:  POSITION'
+            'Print the current turtle position:  POSITION'
             print('Current position is %d %d\n' % position())
         def do_heading(self, arg):
-            'Print the current turle heading in degrees:  HEADING'
+            'Print the current turtle heading in degrees:  HEADING'
             print('Current heading is %d\n' % (heading(),))
         def do_color(self, arg):
             'Set the color:  COLOR BLUE'