[3.7] Fix duplicating words words. (GH-6296) (GH-6297)

Most of them have been added in 3.7.
(cherry picked from commit bac2d5ba30339298db7d4caa9c8cd31d807cf081)
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst
index c1b164e..8d91f4e 100644
--- a/Doc/library/datetime.rst
+++ b/Doc/library/datetime.rst
@@ -2209,8 +2209,8 @@
       :meth:`utcoffset` is transformed into a string of the form
       ±HHMM[SS[.uuuuuu]], where HH is a 2-digit string giving the number of UTC
       offset hours, and MM is a 2-digit string giving the number of UTC offset
-      minutes, SS is a 2-digit string string giving the number of UTC offset
-      seconds and uuuuuu is a 2-digit string string giving the number of UTC
+      minutes, SS is a 2-digit string giving the number of UTC offset
+      seconds and uuuuuu is a 2-digit string giving the number of UTC
       offset microseconds.  The uuuuuu part is omitted when the offset is a
       whole number of minutes and both the uuuuuu and the SS parts are omitted
       when the offset is a whole number of minutes.  For example, if