🐛 typos in the docs (starknet-edu#255)

* fix typo ch00-00-introduction.md

* fix typo ch02-04-katana.md

* fix typo ch02-05-foundry-cast.md

* fix typo ch02-05-testnet-deployment.md

* fix typo ch02-07-01-01-erc20-ui.md

* fix typo ch03-01-01-transactions-lifecycle.md

* fix typo ch03-05-layer-3.md

* fix typo ch03-06-solidity-verifier.md

src/ch02-05-foundry-cast.md

@@ -188,7 +188,7 @@ Points to remember:
 3. **`-private-key`** - Private key of the account.
 4. **`-add-profile`** - Though optional, it's pivotal. By enabling **`sncast`** to include the account in your **`Scarb.toml`** file, you can manage multiple accounts, facilitating transactions among them when working with your smart contract using sncast.
 
-Now that we have familiarized ourselves with using a predeployed account, let's proceed to adding a new account.
+Now that we have familiarized ourselves with using a predeployed account, let's proceed to add a new account.
 
 ### Creating and Deploying a New Account to Starknet Devnet