Fix a bunch of typos in documentation, docstrings and comments.
(From SF patch #810751)
diff --git a/Modules/md5c.c b/Modules/md5c.c
index ee89fec..f9bea0f 100644
--- a/Modules/md5c.c
+++ b/Modules/md5c.c
@@ -141,7 +141,7 @@
 }
 
 /* MD5 finalization. Ends an MD5 message-digest operation, writing the
-  the message digest and zeroing the context.
+  message digest and zeroing the context.
  */
 void
 MD5Final(unsigned char digest[16], MD5_CTX *context)