an -> and typo.

scripts/generate-ffdhe.py

@@ -64,7 +64,7 @@
 # For the INTEGER type (identifier 0x02), the content
 # bytes are simply the bytes of the integer itself in
 # two's complement form, stored in big-endian order.
-# As such, the numbers can be both signed an unsigned.
+# As such, the numbers can be both signed and unsigned.
 # We only implement unsigned integers, since all the
 # numbers we work with in this context are all unsigned.
 # Because two's complement is used, all numbers are signed