Create 24-token-interface-events.md

docs/docs/detectors/24-token-interface-events.md

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+# Token interface events
+
+## Description 
+
+- Category: `Best practices`
+- Severity: `Medium`
+- Detectors: [`token-interface-events`](https://github.com/CoinFabrik/scout-soroban/tree/main/detectors/token-interface-events)
+- Test Cases: [`token-interface-events-1`](https://github.com/CoinFabrik/scout-soroban/tree/main/test-cases/token-interface-events/token-interface-events-1)
+
+
+In Rust, the token contracts have a special interface with certain requirements. One of these requirements is related to events; this requirement states that token functions must emit the events in the specified format. If this does not happen, the contract will have potential errors.
+
+## Why is this bad? 
+
+If the token's functions do not emit events, the contract may have potential errors in handling the token.
+
+## Issue example 
+
+Consider the following `Soroban` contract:
+
+```rust
+
+  fn transfer(env: Env, from: Address, to: Address, amount: i128) {
+        from.require_auth();
+        let from_balance = Self::balance(env.clone(), from.clone());
+        let to_balance = Self::balance(env.clone(), to.clone());
+        assert!(from_balance >= amount);
+        env.storage()
+            .instance()
+            .set(&DataKey::Balance(from), &(from_balance - amount));
+        env.storage()
+            .instance()
+            .set(&DataKey::Balance(to), &(to_balance + amount));
+    }
+
+```
+
+In this example, the `transfer()` function does not emit an event.
+
+The code example can be found [here](https://github.com/CoinFabrik/scout-soroban/tree/main/test-cases/token-interface-events/token-interface-events-1/vulnerable-example).
+
+
+## Remediated example
+
+```rust
+  fn transfer(env: Env, from: Address, to: Address, amount: i128) {
+        from.require_auth();
+        let from_balance = Self::balance(env.clone(), from.clone());
+        let to_balance = Self::balance(env.clone(), to.clone());
+        assert!(from_balance >= amount);
+        env.storage()
+            .instance()
+            .set(&DataKey::Balance(from.clone()), &(from_balance - amount));
+        env.storage()
+            .instance()
+            .set(&DataKey::Balance(to.clone()), &(to_balance + amount));
+
+        TokenUtils::new(&env).events().transfer(from, to, amount);
+    }
+```
+In this example, the `transfer()` function emits an event.
+
+The remediated code example can be found [here](https://github.com/CoinFabrik/scout-soroban/tree/main/test-cases/token-interface-events/token-interface-events-1/remediated-example).
+
+## How is it detected?
+
+If the token interface trait is being used, check if all of the token's functions emit events. 
+
+
+
+