Add pink precompile docs (#67)

docs/build/precompiles/overview.md

@@ -18,6 +18,7 @@ In the comprehensive Darwinia Ecosystem, each network serves a distinct purpose,
 | `0x0000000000000000000000000000000000000401` | [Dispatch](../precompiles/dispatch.md) |
 | `0x0000000000000000000000000000000000000402` | [Commitment Token](../precompiles/commitment-token.md) |
 | `0x0000000000000000000000000000000000000403` | [USDT](../precompiles/usdt.md) |
+| `0x0000000000000000000000000000000000000404` | [PINK](../precompiles/pink.md) |
 | `0x0000000000000000000000000000000000000600` | [Deposit](../precompiles/deposit.md) |
 | `0x0000000000000000000000000000000000000601` | [Staking](../precompiles/staking.md) |
 | `0x0000000000000000000000000000000000000800` | BLS12-381 |

docs/build/precompiles/pink.md

@@ -0,0 +1,11 @@
+# PINK Precompile
+
+We recently introduced [PINK Memecoin](https://coinmarketcap.com/community/articles/65fd2671054c8374b8b312c7/), a new addition to the Polkadot ecosystem designed to boost community engagement and participation. Launched by Polkadot Web3, this innovative token takes inspiration from Polkadot's RGB color code and has a total supply of 2.3 billion tokens. This move demonstrates Polkadot's commitment to inclusivity and equitable rewards for active contributors and community members.
+
+For users who want to interact with PINK, we provide a dedicated precompile for this purpose. You can use it in the same way you would use an ERC-20 token.
+
+## Contract Info
+
+- The default contract address:  0x0000000000000000000000000000000000000404
+- [The interface](https://github.com/darwinia-network/darwinia/blob/main/precompile/metadata/sol/asset.sol)
+- [The ABI](https://github.com/darwinia-network/darwinia/blob/main/precompile/metadata/sol/asset.sol)

docs/build/precompiles/usdt.md

@@ -4,11 +4,6 @@ Tether (USDT) is a widely used stablecoin in the crypto world. It has been [inte
 
 In order to improve the compatibility of USDT with Ethereum-based tools and workflows, a dedicated precompile has been developed. This precompile acts as a bridge, simplifying the interaction between Ethereum users and USDT. By leveraging this precompile, Ethereum users can seamlessly interact with USDT using their familiar Ethereum tools, such as MetaMask.
 
-!!! Warning
-    As of 2023-11-21, the USDT functionality is only enabled for testing purposes in the Pangolin Testnet. We have plans to enable this in the Darwinia in the future.
-
-</aside>
-
 ## Contract Info
 
 - The default contract address:  0x0000000000000000000000000000000000000403

mkdocs.yml

@@ -374,6 +374,7 @@ nav:
             - Overview: "build/precompiles/overview.md"
             - Asset:
               - KTON: "build/precompiles/commitment-token.md"
+              - PINK: "build/precompiles/pink.md"
               - USDT: "build/precompiles/usdt.md"
             - Staking:
               - Staking: "build/precompiles/staking.md"