Merge bitcoin#742: Fix typo in ecmult_const_impl.h

4e28465 Fix typo in ecmult_const_impl.h (f-daniel)

Pull request description:

  Fix small typo in the reference given for the wNAF method ( `secp256k1_wnaf_const`)

ACKs for top commit:
  real-or-random:
    ACK 4e28465 trivial

Tree-SHA512: d6c3daa0384fc1bba36a46933641c97661b18e88c711343e2c8f91f39aa707eddd0ba77c8d5c43aaead883eeed7f4458ed1dec228d692d713572231aa6010fb0

src/ecmult_const_impl.h

@@ -46,7 +46,7 @@
  *
  *  Adapted from `The Width-w NAF Method Provides Small Memory and Fast Elliptic Scalar
  *  Multiplications Secure against Side Channel Attacks`, Okeya and Tagaki. M. Joye (Ed.)
- *  CT-RSA 2003, LNCS 2612, pp. 328-443, 2003. Springer-Verlagy Berlin Heidelberg 2003
+ *  CT-RSA 2003, LNCS 2612, pp. 328-443, 2003. Springer-Verlag Berlin Heidelberg 2003
  *
  *  Numbers reference steps of `Algorithm SPA-resistant Width-w NAF with Odd Scalar` on pp. 335
  */