Merge #381: Fix typo in documentation

47411ce Fix typo in documentation (Tobin Harding)

Pull request description:

  Docs reference a function name but there is a typo.

  'grund' -> 'grind'.

ACKs for top commit:
  apoelstra:
    ACK 47411ce

Tree-SHA512: e6724f1c7972625d59be0ae9de358295c9280e2e126e7322d706cbdca342c1189552b2fdeef9370ff4f85ea8ef185ef4447f6693979d5e8548fcfa2df41a491e

Author: apoelstra

src/ecdsa/mod.rs

@@ -381,7 +381,7 @@ impl<C: Signing> Secp256k1<C> {
 
     /// Constructs a signature for `msg` using the secret key `sk`, RFC6979 nonce
     /// and "grinds" the nonce by passing extra entropy if necessary to produce
-    /// a signature that is less than 71 - bytes_to_grund bytes. The number
+    /// a signature that is less than 71 - `bytes_to_grind` bytes. The number
     /// of signing operation performed by this function is exponential in the
     /// number of bytes grinded.
     /// Requires a signing capable context.
@@ -392,7 +392,7 @@ impl<C: Signing> Secp256k1<C> {
 
     /// Constructs a signature for `msg` using the secret key `sk`, RFC6979 nonce
     /// and "grinds" the nonce by passing extra entropy if necessary to produce
-    /// a signature that is less than 71 - bytes_to_grund bytes. The number
+    /// a signature that is less than 71 - `bytes_to_grind` bytes. The number
     /// of signing operation performed by this function is exponential in the
     /// number of bytes grinded.
     /// Requires a signing capable context.