Coverage exclusion -- this is just an extra, redundant check

src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c

@@ -48,7 +48,7 @@ crypto_scalarmult_ed25519(unsigned char *q, const unsigned char *n,
     ge25519_scalarmult(&Q, t, &P);
     ge25519_p3_tobytes(q, &Q);
     if (_crypto_scalarmult_ed25519_is_inf(q) != 0) {
-        return -1;
+        return -1; /* LCOV_EXCL_LINE */
     }
     return 0;
 }