mmr: add mmr feature

Author: nostronaut

crates/nostr/Cargo.toml

@@ -25,6 +25,7 @@ nip19 = ["dep:bech32"]
 nip21 = ["nip19"]
 nip46 = ["nip04"]
 nip47 = ["nip04"]
+mmr = []
 
 [dependencies]
 aes = { version = "0.8", optional = true }

crates/nostr/src/event/builder.rs

@@ -172,6 +172,7 @@ impl EventBuilder {
     }
 
     /// Build MMR [`Event`]
+    #[cfg(feature = "mmr")]
     pub fn to_mmr_event(
         self,
         keys: &Keys,
@@ -186,6 +187,7 @@ impl EventBuilder {
     }
 
     /// Build unsigned MMR [`Event`]
+    #[cfg(feature = "mmr")]
     pub fn to_unsigned_mmr_event(
         self,
         pubkey: XOnlyPublicKey,