Rename token doc's approve arg to live_until_ledger

docs/build/smart-contracts/example-contracts/tokens.mdx

@@ -35,7 +35,7 @@ This example shows how to build a token from scratch using only the `soroban-sdk
 
 [open-in-github-codespaces]: https://github.com/codespaces/new?repo=stellar/soroban-examples&editor=web
 [open-in-code-anywhere]: https://app.codeanywhere.com/#https://github.com/stellar/soroban-examples
-[token example]: https://github.com/stellar/soroban-examples/tree/v23.0.0/token
+[token example]: https://github.com/stellar/soroban-examples/tree/main/token
 [token interface]: ../../../tokens/token-interface.mdx
 
 :::info[Whisk Changes]
@@ -46,10 +46,10 @@ With the release of Whisk, Protocol 23, the [token interface] has seen some chan
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v23.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `soroban-examples` repository:
 
 ```sh
-git clone -b v23.0.0 https://github.com/stellar/soroban-examples
+git clone https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [GitHub Codespaces][open-in-github-codespaces] or [Code Anywhere][open-in-code-anywhere].
@@ -129,18 +129,18 @@ use soroban_sdk::{Address, Env};
 pub fn read_allowance(e: &Env, from: Address, spender: Address) -> AllowanceValue {
     let key = DataKey::Allowance(AllowanceDataKey { from, spender });
     if let Some(allowance) = e.storage().temporary().get::<_, AllowanceValue>(&key) {
-        if allowance.expiration_ledger < e.ledger().sequence() {
+        if allowance.live_until_ledger < e.ledger().sequence() {
             AllowanceValue {
                 amount: 0,
-                expiration_ledger: allowance.expiration_ledger,
+                live_until_ledger: allowance.live_until_ledger,
             }
         } else {
             allowance
         }
     } else {
         AllowanceValue {
             amount: 0,
-            expiration_ledger: 0,
+            live_until_ledger: 0,
         }
     }
 }
@@ -150,22 +150,22 @@ pub fn write_allowance(
     from: Address,
     spender: Address,
     amount: i128,
-    expiration_ledger: u32,
+    live_until_ledger: u32,
 ) {
     let allowance = AllowanceValue {
         amount,
-        expiration_ledger,
+        live_until_ledger,
     };
 
-    if amount > 0 && expiration_ledger < e.ledger().sequence() {
-        panic!("expiration_ledger is less than ledger seq when amount > 0")
+    if amount > 0 && live_until_ledger < e.ledger().sequence() {
+        panic!("live_until_ledger is less than ledger seq when amount > 0")
     }
 
     let key = DataKey::Allowance(AllowanceDataKey { from, spender });
     e.storage().temporary().set(&key.clone(), &allowance);
 
     if amount > 0 {
-        let live_for = expiration_ledger
+        let live_for = live_until_ledger
             .checked_sub(e.ledger().sequence())
             .unwrap();
 
@@ -184,7 +184,7 @@ pub fn spend_allowance(e: &Env, from: Address, spender: Address, amount: i128) {
             from,
             spender,
             allowance.amount - amount,
-            allowance.expiration_ledger,
+            allowance.live_until_ledger,
         );
     }
 }
@@ -319,7 +319,7 @@ impl Token {
     }
 }
 
-#[contractimpl]
+#[contractimpl(contracttrait)]
 impl TokenInterface for Token {
     fn allowance(e: Env, from: Address, spender: Address) -> i128 {
         e.storage()
@@ -328,7 +328,7 @@ impl TokenInterface for Token {
         read_allowance(&e, from, spender).amount
     }
 
-    fn approve(e: Env, from: Address, spender: Address, amount: i128, expiration_ledger: u32) {
+    fn approve(e: Env, from: Address, spender: Address, amount: i128, live_until_ledger: u32) {
         from.require_auth();
 
         check_nonnegative_amount(amount);
@@ -337,12 +337,12 @@ impl TokenInterface for Token {
             .instance()
             .extend_ttl(INSTANCE_LIFETIME_THRESHOLD, INSTANCE_BUMP_AMOUNT);
 
-        write_allowance(&e, from.clone(), spender.clone(), amount, expiration_ledger);
+        write_allowance(&e, from.clone(), spender.clone(), amount, live_until_ledger);
         events::Approve {
             from,
             spender,
             amount,
-            expiration_ledger,
+            expiration_ledger: live_until_ledger,
         }
         .publish(&e);
     }
@@ -489,7 +489,7 @@ pub struct AllowanceDataKey {
 #[contracttype]
 pub struct AllowanceValue {
     pub amount: i128,
-    pub expiration_ledger: u32,
+    pub live_until_ledger: u32,
 }
 
 #[derive(Clone)]
@@ -505,7 +505,7 @@ pub enum DataKey {
 </TabItem>
 </Tabs>
 
-Ref: https://github.com/stellar/soroban-examples/tree/v23.0.0/token
+Ref: https://github.com/stellar/soroban-examples/tree/main/token
 
 ## How it Works
 
@@ -599,7 +599,7 @@ Of course, you will want your token to behave in an _intuitive_ and _transparent
 
 ## Tests
 
-Open the [`token/src/test.rs`](https://github.com/stellar/soroban-examples/tree/v23.0.0/token/src/test.rs) file to follow along.
+Open the [`token/src/test.rs`](https://github.com/stellar/soroban-examples/tree/main/token/src/test.rs) file to follow along.
 
 ```rust title="token/src/test.rs"
 #![cfg(test)]
@@ -877,7 +877,7 @@ fn test_zero_allowance() {
 }
 ```
 
-The token example implements eight different tests to cover a wide array of potential behaviors and problems. However, all of the tests start with a few common pieces. In any test, the first thing that is always required is an `Env`, which is the Soroban environment that the contract will run in.
+The token example implements six different tests to cover a wide array of potential behaviors and problems. However, all of the tests start with a few common pieces. In any test, the first thing that is always required is an `Env`, which is the Soroban environment that the contract will run in.
 
 ```rust
 let e = Env::default();