examples: Remove crate imports

Now we have edition 2018 we no longer need to import crates in the
examples, either using `extern` or otherwise.

Remove crate imports, including `extern crate`.

Author: tcharding

examples/htlc.rs

@@ -14,9 +14,6 @@
 
 //! Example: Create an HTLC with miniscript using the policy compiler
 
-extern crate bitcoin;
-extern crate miniscript;
-
 use bitcoin::Network;
 use miniscript::descriptor::Wsh;
 use miniscript::policy::{Concrete, Liftable};

examples/parse.rs

@@ -14,9 +14,6 @@
 
 //! Example: Parsing a descriptor from a string
 
-use bitcoin;
-use miniscript;
-
 use miniscript::{descriptor::DescriptorType, Descriptor, DescriptorTrait};
 use std::str::FromStr;
 

examples/psbt.rs

@@ -1,5 +1,3 @@
-use bitcoin;
-
 use bitcoin::consensus::encode::deserialize;
 use bitcoin::hashes::hex::FromHex;
 use miniscript::psbt::PsbtExt;

examples/sign_multisig.rs

@@ -14,9 +14,6 @@
 
 //! Example: Signing a 2-of-3 multisignature
 
-use bitcoin;
-use miniscript;
-
 use bitcoin::blockdata::witness::Witness;
 use bitcoin::secp256k1; // secp256k1 re-exported from rust-bitcoin
 use miniscript::DescriptorTrait;

examples/verify_tx.rs

@@ -14,9 +14,6 @@
 
 //! Example: Verifying a signed transaction
 
-use bitcoin;
-use miniscript;
-
 use bitcoin::consensus::Decodable;
 use bitcoin::util::sighash;
 use bitcoin::{secp256k1, TxOut}; // secp256k1 re-exported from rust-bitcoin