[3.8] Fix typos in docs, comments and test assert messages (GH-14872). (#14900)

(cherry picked from commit 96e12d5f4f3c5a20986566038ee763dff3c228a1)

Co-authored-by: Min ho Kim <minho42@gmail.com>
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 34e11bd..0a59757 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -2119,7 +2119,7 @@
         /* How many bytes do we need?  There are nbits >> 3 full
          * bytes of data, and nbits & 7 leftover bits.  If there
          * are any leftover bits, then we clearly need another
-         * byte.  Wnat's not so obvious is that we *probably*
+         * byte.  What's not so obvious is that we *probably*
          * need another byte even if there aren't any leftovers:
          * the most-significant bit of the most-significant byte
          * acts like a sign bit, and it's usually got a sense