add slip-0173 to README

README.md

@@ -24,6 +24,7 @@ Each SLIP should provide a concise technical specification of the feature and a
 | [SLIP-0017](slip-0017.md) | Elliptic Curve Diffie-Hellman using deterministic hierarchy           | Standard      | Draft    |
 | [SLIP-0044](slip-0044.md) | Registered coin types for BIP-0044                                    | Standard      | Draft    |
 | [SLIP-0048](slip-0048.md) | Deterministic key hierarchy for Graphene-based networks               | Informational | Draft    |
+| [SLIP-0173](slip-0173.md) | Registered human-readable parts for BIP-0173                          | Standard      | Draft    |
 
 ---
 

slip-0173.md

@@ -21,10 +21,12 @@ The BIP repository does not want to deal with assigning the values for various c
 
 These are the registered human-readable parts for usage in Bech32 encoding of witness programs.
 
-hrp  | coin
------|--------------------------------
-`bc` | [Bitcoin](https://bitcoin.org/)
-`tb` | Bitcoin Testnet
+hrp    | coin
+-------|--------------------------------
+`bc`   | [Bitcoin](https://bitcoin.org/)
+`tb`   | Bitcoin Testnet
+`ltc`  | [Litecoin](https://litecoin.org/)
+`tltc` | Litecoin Testnet
 
 ## Libraries