Add get_nonce docs (#1302)

<!-- Reference any GitHub issues resolved by this PR -->

Closes #1197

## Introduced changes

<!-- A brief description of the changes -->

- add get_nonce docs, update examples

## Checklist

<!-- Make sure all of these are complete -->

- [X] Linked relevant issue
- [X] Updated relevant documentation
- [X] Added relevant tests
- [X] Performed self-review of the code
- [X] Added changes to `CHANGELOG.md`

---------

Co-authored-by: Maksim Zdobnikau <[email protected]>

Author: THenry14

docs/src/SUMMARY.md

@@ -96,3 +96,4 @@
     * [deploy](appendix/cast-library/deploy.md)
     * [invoke](appendix/cast-library/invoke.md)
     * [call](appendix/cast-library/call.md)
+    * [get_nonce](appendix/cast-library/get_nonce.md)

docs/src/appendix/cast-library.md

@@ -4,6 +4,7 @@
 * [`deploy`](cast-library/deploy.md) - deploys a contract
 * [`invoke`](cast-library/invoke.md) - invokes a contract's function
 * [`call`](cast-library/call.md) - calls a contract's function
+* [`get_nonce`](cast-library/get_nonce.md) - gets account's nonce for a given block tag
 
 > ℹ️ **Info**
 > To use the library functions you need to add `sncast_std` package as a dependency in

docs/src/appendix/cast-library/get_nonce.md

@@ -0,0 +1,17 @@
+# `get_nonce`
+
+> `fn get_nonce(block_tag: felt252) -> felt252`
+
+Gets nonce of an account for a given block tag (`pending` or `latest`) and returns nonce as `felt252`.
+
+- `block_tag` - block tag name, one of `pending` or `latest`.
+
+```rust
+use sncast_std::{get_nonce};
+use debug::PrintTrait;
+
+fn main() {
+    let nonce = get_once('latest');
+    nonce.print();
+}
+```

docs/src/starknet/script.md

@@ -87,26 +87,28 @@ This example script declares, deploys and interacts with an example [map contrac
 
 ```cairo
 use sncast_std::{
-    declare, deploy, invoke, call, DeclareResult, DeployResult, InvokeResult, CallResult
+    declare, deploy, invoke, call, DeclareResult, DeployResult, InvokeResult, CallResult, get_nonce
 };
 use debug::PrintTrait;
 
 fn main() {
     let max_fee = 99999999999999999;
     let salt = 0x3;
+    let nonce = get_nonce('latest');
 
-    let declare_result = declare('Map', Option::Some(max_fee));
+    let declare_result = declare('Map', Option::Some(max_fee), Option::Nonce);
 
     let class_hash = declare_result.class_hash;
     let deploy_result = deploy(
-        class_hash, ArrayTrait::new(), Option::Some(salt), true, Option::Some(max_fee)
+        class_hash, ArrayTrait::new(), Option::Some(salt), true, Option::Some(max_fee), Option::Some(nonce)
     );
     
     'Deployed the contract to address'.print();
     deploy_result.contract_address.print();
 
+    let invoke_nonce = get_nonce('pending');
     let invoke_result = invoke(
-        deploy_result.contract_address, 'put', array![0x1, 0x2], Option::Some(max_fee)
+        deploy_result.contract_address, 'put', array![0x1, 0x2], Option::Some(max_fee), Option::Some(invoke_nonce)
     );
     
     'Invoke tx hash is'.print();