chore: update public key recovery example in docs (#1638)

When viewing the [docs hub
example](https://docs.fuel.network/docs/fuels-rs/wallets/signing/#signing)
on how to recover a public key, the variable name provided is
`recovered_address`. This is misleading and leads to confusion as the
recovered type is a `PublicKey`
https://github.com/FuelLabs/fuel-vm/blob/09c500838b734603970c62d414e0e95825f44773/fuel-crypto/src/secp256/signature.rs#L140C56-L140C65.
This has been updated to a more appropriate name.

# Checklist

- [x] All **changes** are **covered** by **tests** (or not applicable)
- [x] All **changes** are **documented** (or not applicable)
- [x] I **reviewed** the **entire PR** myself (preferably, on GH UI)
- [x] I **described** all **Breaking Changes** (or there's none)

Author: bitzoic

packages/fuels-accounts/src/signers/private_key.rs

@@ -109,13 +109,13 @@ mod tests {
             )?
         );
 
-        // Recover address that signed the message
-        let recovered_address = signature.recover(&message)?;
+        // Recover the public key that signed the message
+        let recovered_pub_key: PublicKey = signature.recover(&message)?;
 
-        assert_eq!(signer.address().hash(), recovered_address.hash());
+        assert_eq!(signer.address().hash(), recovered_pub_key.hash());
 
         // Verify signature
-        signature.verify(&recovered_address, &message)?;
+        signature.verify(&recovered_pub_key, &message)?;
         // ANCHOR_END: sign_message
 
         Ok(())