Merge #416: Fix grammar 'any' -> 'an'

a84a238 Fix grammar 'any' -> 'an' (Tobin C. Harding)

Pull request description:

  Do minor grammar improvement. This is a nit from review of #386 (review)

ACKs for top commit:
  sanket1729:
    ACK a84a238

Tree-SHA512: a9b08fb7a28a10958b8d2ecdf103fa4e7e6240d9217b3b5468aff423f7d6e6cae7e2980469f206f4316a91b29d1cfc8282d8dc563acce299b3925f3f2296a5c7

Author: sanket1729

src/descriptor/mod.rs

@@ -320,10 +320,10 @@ impl<Pk: MiniscriptKey> Descriptor<Pk> {
 impl<Pk: MiniscriptKey + ToPublicKey> Descriptor<Pk> {
     /// Computes the Bitcoin address of the descriptor, if one exists
     ///
-    /// Some descriptors like pk() don't have any address.
+    /// Some descriptors like pk() don't have an address.
     ///
     /// # Errors
-    /// For raw/bare descriptors that don't have any address.
+    /// For raw/bare descriptors that don't have an address.
     pub fn address(&self, network: Network) -> Result<Address, Error> {
         match *self {
             Descriptor::Bare(_) => Err(Error::BareDescriptorAddr),