Add OKX Web3 Wallet to list of wallets that support Celo. Closes #1873 (#1872)

* Update index.md with OKX Wallet

* Maintainers

* Space

* Grammar

* Improvements by @GigaHierz

Author: vtamara

docs/wallet/index.md

@@ -302,3 +302,14 @@ With Zerion’s infrastructure you can build feature-rich real-time web3 apps, w
 - Homepage: [zerion.io](https://zerion.io/)
 - Platforms: Browser, iOS, Android
 - [Source Code](https://developers.zerion.io/reference/getting-started)
+
+---
+
+### [OKX Web3 Wallet](https://web3.okx.com/)
+
+Supports over 130 blockchains, including CELO. Enables users to store, trade, analyze, earn, and connect to Web3 sites. The mobile app features a built-in browser for seamless Web3 access and includes a tab to switch to the OKX exchange (though creating an exchange account is not required to use the wallet). It’s fully compatible with WalletConnect and widely supported across Web3 platforms.
+
+- Homepage: [web3.okx.com](https://web3.okx.com/)
+- Platforms: [iOS](https://apps.apple.com/us/app/okx-wallet-portal-to-web3/id6743309484), [Android](https://play.google.com/store/apps/details?id=com.okx.wallet), [Chrome, Brave, Opera, & Edge Browser](https://chromewebstore.google.com/detail/okx-wallet/mcohilncbfahbmgdjkbpemcciiolgcge), [Telegram](https://web.telegram.org/k/#@OKX_WALLET_BOT)
+- Maintainers: [OKX](https://okx.com/)
+- Source code is not available, although there are two repositories related and useful for developers: https://github.com/okx/go-wallet-sdk and https://github.com/okx/js-wallet-sdk