Hyperlink DOI to preferred resolver

Change-Id: Ib9983a74d5d2f8be7c96cedde17be5a4e9223d5e
Reviewed-on: https://boringssl-review.googlesource.com/c/34844
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>

crypto/fipsmodule/bn/prime.c

diff --git a/crypto/fipsmodule/bn/prime.c b/crypto/fipsmodule/bn/prime.c
index b417d4f..1f3510d 100644
--- a/crypto/fipsmodule/bn/prime.c
+++ b/crypto/fipsmodule/bn/prime.c
@@ -316,7 +316,7 @@
 //
 // This table is generated using the algorithm of FIPS PUB 186-4
 // Digital Signature Standard (DSS), section F.1, page 117.
-// (https://dx.doi.org/10.6028/NIST.FIPS.186-4)
+// (https://doi.org/10.6028/NIST.FIPS.186-4)
 // The following magma script was used to generate the output:
 // securitybits:=125;
 // k:=1024;