Merge rust-bitcoin/rust-bitcoin#1397: Add Network::to_core_arg() method

519db4d951 add Network::to_core_arg() method (connormullett)

Pull request description:

  closes: #1207

  Adds converting `Network` to its `bitcoind` equivalent.
  The arguments for -chain can be found in the documentation and is one of the following:
  main, test, signet, regtest

ACKs for top commit:
  apoelstra:
    ACK 519db4d951
  Kixunil:
    ACK 519db4d951

Tree-SHA512: 5fd805d654f7c30f87ff877fe90e19490d0deb73b46ce87cc6b43d30595eb9d2de3f646f58a5d72180c3e8cc6a9b614bfe6753ecd6c21b8d193a8d862e3f887f

bitcoin/src/network/constants.rs

@@ -101,6 +101,24 @@ impl Network {
     /// assert_eq!(network.magic(), Magic::from_bytes([0xF9, 0xBE, 0xB4, 0xD9]));
     /// ```
     pub fn magic(self) -> Magic { Magic::from(self) }
+
+    /// Converts a `Network` to its equivalent `bitcoind -chain` argument name.
+    ///
+    /// ```bash,no_run
+    /// $ bitcoin-23.0/bin/bitcoind --help | grep -C 3 '\-chain=<chain>'
+    /// Chain selection options:
+    ///
+    /// -chain=<chain>
+    /// Use the chain <chain> (default: main). Allowed values: main, test, signet, regtest
+    /// ```
+    pub fn to_core_arg(self) -> &'static str {
+        match self {
+            Network::Bitcoin => "main",
+            Network::Testnet => "test",
+            Network::Signet => "signet",
+            Network::Regtest => "regtest",
+        }
+    }
 }
 
 /// An error in parsing network string.