cleanup docs and examples

lang/attribute/program/src/lib.rs

@@ -18,6 +18,35 @@ pub fn program(
 /// The `#[interface]` attribute is used to mark an instruction as belonging
 /// to an interface implementation, thus transforming its discriminator to the
 /// proper bytes for that interface instruction.
+///
+/// # Example
+///
+/// ```rust,ignore
+/// use anchor_lang::prelude::*;
+///
+/// // SPL Transfer Hook Interface: `Execute` instruction.
+/// //
+/// // This instruction is invoked by Token-2022 when a transfer occurs,
+/// // if a mint has specified this program as its transfer hook.
+/// #[interface(spl_transfer_hook_interface::execute)]
+/// pub fn execute_transfer(ctx: Context<Execute>, amount: u64) -> Result<()> {
+///     // Check that all extra accounts were provided
+///     let data = ctx.accounts.extra_metas_account.try_borrow_data()?;
+///     ExtraAccountMetaList::check_account_infos::<ExecuteInstruction>(
+///         &ctx.accounts.to_account_infos(),
+///         &TransferHookInstruction::Execute { amount }.pack(),
+///         &ctx.program_id,
+///         &data,
+///     )?;
+///
+///     // Or maybe perform some custom logic
+///     if ctx.accounts.token_metadata.mint != ctx.accounts.token_account.mint {
+///         return Err(ProgramError::IncorrectAccount);
+///     }
+///
+///     Ok(())
+/// }
+/// ```
 #[cfg(feature = "interface-instructions")]
 #[proc_macro_attribute]
 pub fn interface(

tests/spl/transfer-hook/programs/transfer-hook/src/lib.rs

@@ -119,7 +119,6 @@ pub struct Initialize<'info> {
 }
 
 #[derive(Accounts)]
-#[instruction(amount: u64)]
 pub struct Execute<'info> {
     #[account(
         token::mint = mint,

ts/packages/anchor/src/program/namespace/methods.ts

@@ -166,7 +166,6 @@ export class MethodsBuilder<IDL extends Idl, I extends AllInstructions<IDL>> {
     >;
   }
 
-  // TODO: Remove the hard-coded discriminators once we have a JS package for Transfer Hook
   public interface(splInterface: SplInterface): MethodsBuilder<IDL, I> {
     if (
       splInterface ===