Correct Serai header on genesis

Includes a couple misc fixes for the RPC as well.

substrate/client/serai/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/substrate/client/s
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["serai"]
 edition = "2021"
-rust-version = "1.85"
+rust-version = "1.89"
 
 [package.metadata.docs.rs]
 all-features = true

substrate/client/serai/src/lib.rs

@@ -153,8 +153,7 @@ impl Serai {
 
   /// Fetch a block from the Serai blockchain by its number.
   pub async fn block_by_number(&self, block: u64) -> Result<Block, RpcError> {
-    Self::block_internal(self.call("blockchain/block", &format!(r#"{{ "block": "{block}" }}"#)))
-      .await
+    Self::block_internal(self.call("blockchain/block", &format!(r#"{{ "block": {block} }}"#))).await
   }
 
   /// Scope this RPC client to the state as of a specific block.

substrate/client/serai/src/validator_sets.rs

@@ -100,7 +100,7 @@ impl<'a> ValidatorSets<'a> {
         .0
         .call::<Option<_>>(
           "validator-sets/session",
-          &format!(r#" "network": {} "#, rpc_network(network)?),
+          &format!(r#", "network": {} "#, rpc_network(network)?),
         )
         .await?
         .map(Session),
@@ -114,7 +114,7 @@ impl<'a> ValidatorSets<'a> {
         .0
         .call::<Option<_>>(
           "validator-sets/current_stake",
-          &format!(r#" "network": {} "#, rpc_network(network)?),
+          &format!(r#", "network": {} "#, rpc_network(network)?),
         )
         .await?
         .map(Amount),
@@ -128,7 +128,7 @@ impl<'a> ValidatorSets<'a> {
       .call::<Option<String>>(
         "validator-sets/keys",
         &format!(
-          r#" "set": {{ "network": {}, "session": {} }} "#,
+          r#", "set": {{ "network": {}, "session": {} }} "#,
           rpc_network(set.network)?,
           set.session.0
         ),