Issue #17047: remove doubled words found in 2.7 to 3.4 Modules/*,
as reported by Serhiy Storchaka and Matthew Barnett.
diff --git a/Modules/expat/xmltok.c b/Modules/expat/xmltok.c
index bf09dfc..b9cd7a4 100644
--- a/Modules/expat/xmltok.c
+++ b/Modules/expat/xmltok.c
@@ -1584,7 +1584,7 @@
       if (ptr[0] == '\0') {
         /* 0 isn't a legal data character. Furthermore a document
            entity can only start with ASCII characters.  So the only
-           way this can fail to be big-endian UTF-16 if it it's an
+           way this can fail to be big-endian UTF-16 is if it is an
            external parsed general entity that's labelled as
            UTF-16LE.
         */