Use snippet anchor instead of line range

snippets/rust/src/lnurl_withdraw.rs

@@ -4,6 +4,7 @@ use anyhow::Result;
 use breez_sdk_core::*;
 
 async fn withdraw(sdk: Arc<BreezServices>) -> Result<()> {
+    // ANCHOR: lnurl-withdraw
     // Endpoint can also be of the form:
     // lnurlw://domain.com/lnurl-withdraw?key=val
     let lnurl_withdraw_url = "lnurl1dp68gurn8ghj7mr0vdskc6r0wd6z7mrww4exctthd96xserjv9mn7um9wdekjmmw843xxwpexdnxzen9vgunsvfexq6rvdecx93rgdmyxcuxverrvcursenpxvukzv3c8qunsdecx33nzwpnvg6ryc3hv93nzvecxgcxgwp3h33lxk";
@@ -14,6 +15,7 @@ async fn withdraw(sdk: Arc<BreezServices>) -> Result<()> {
 
         sdk.lnurl_withdraw(wd, amount_msat, Some(description)).await?;
     }
+    // ANCHOR_END: lnurl-withdraw
 
     Ok(())
 }