chore(provider): document privileged status of EIP-1559 (alloy-rs#850)

* document priviledged status of EIP-1559

* fix typo

* hf -> tx type

* doc: update 1559 note

---------

Co-authored-by: James <[email protected]>

crates/provider/src/provider/trait.rs

@@ -33,15 +33,34 @@ pub type FilterPollerBuilder<T, R> = PollerBuilder<T, (U256,), Vec<R>>;
 ///
 /// # Subscriptions
 ///
-/// **IMPORTANT:** this is currently only available when `T` is `PubSubFrontend` or `BoxedClient`
-/// over `PubSubFrontend` due to an internal limitation. This means that layering transports will
-/// always disable subscription support. See [issue #296](https://github.com/alloy-rs/alloy/issues/296).
+/// **IMPORTANT:** this is currently only available when `T` is
+/// `PubSubFrontend` or `BoxedClient` over `PubSubFrontend` due to an internal
+/// limitation. This means that layering transports will always disable
+/// subscription support. See
+/// [issue #296](https://github.com/alloy-rs/alloy/issues/296).
 ///
-/// The provider supports `pubsub` subscriptions to new block headers and pending transactions. This
-/// is only available on `pubsub` clients, such as WebSockets or IPC.
+/// The provider supports `pubsub` subscriptions to new block headers and
+/// pending transactions. This is only available on `pubsub` clients, such as
+/// Websockets or IPC.
 ///
-/// For a polling alternatives available over HTTP, use the `watch_*` methods. However, be aware
-/// that polling increases RPC usage drastically.
+/// For a polling alternatives available over HTTP, use the `watch_*` methods.
+/// However, be aware that polling increases RPC usage drastically.
+///
+/// ## Special treatment of EIP-1559
+///
+/// While many RPC features are encapsulated by traits like [`DebugApi`],
+/// EIP-1559 fee estimation is generally assumed to be on by default. We
+/// generally assume that EIP-1559 is supported by the client and will
+/// proactively use it by default.
+///
+/// As a result, the provider supports EIP-1559 fee estimation the ethereum
+/// [`TransactionBuilder`] will use it by default. We acknowledge that this
+/// means EIP-1559 has a privileged status in comparison to other transaction
+/// types. Networks that DO NOT support EIP-1559 should create their own
+/// [`TransactionBuilder`] and Fillers to change this behavior.
+///
+/// [`TransactionBuilder`]: alloy_network::TransactionBuilder
+/// [`DebugApi`]: crate::ext::DebugApi
 #[cfg_attr(target_arch = "wasm32", async_trait::async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait::async_trait)]
 #[auto_impl::auto_impl(&, &mut, Rc, Arc, Box)]
@@ -790,8 +809,8 @@ pub trait Provider<T: Transport + Clone = BoxTransport, N: Network = Ethereum>:
             )
             .await?;
 
-        // if the base fee of the Latest block is 0 then we need check if the latest block even has
-        // a base fee/supports EIP1559
+        // If the base fee of the Latest block is 0 then we need check if the latest block even has
+        // a base fee/supports EIP1559.
         let base_fee_per_gas = match fee_history.latest_block_base_fee() {
             Some(base_fee) if (base_fee != 0) => base_fee,
             _ => {