Update some www.unicode.org URLs to use HTTPS. (GH-18912)
diff --git a/Objects/stringlib/codecs.h b/Objects/stringlib/codecs.h
index eb42e07..39c1553 100644
--- a/Objects/stringlib/codecs.h
+++ b/Objects/stringlib/codecs.h
@@ -153,7 +153,7 @@
/* Decoding UTF-8 sequences in range \xED\xA0\x80-\xED\xBF\xBF
will result in surrogates in range D800-DFFF. Surrogates are
not valid UTF-8 so they are rejected.
- See http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf
+ See https://www.unicode.org/versions/Unicode5.2.0/ch03.pdf
(table 3-7) and http://www.rfc-editor.org/rfc/rfc3629.txt */
goto InvalidContinuation1;
}