docs(wasm-dpp): document no-op user fee increase methods on vote transition (#3209)

Co-authored-by: PastaClaw <thepastaclaw@users.noreply.github.com>

Author: thepastaclaw

packages/wasm-dpp/src/voting/state_transition/masternode_vote_transition/mod.rs

@@ -223,11 +223,15 @@ impl MasternodeVoteTransitionWasm {
         self.0.is_voting_state_transition()
     }
 
+    /// Masternode vote transitions do not support user fee increase; always returns 0.
+    /// This method is kept for API compatibility.
     #[wasm_bindgen(js_name=getUserFeeIncrease)]
     pub fn get_user_fee_increase(&self) -> u16 {
         0
     }
 
+    /// Masternode vote transitions do not support user fee increase.
+    /// This method is kept for API compatibility and intentionally does nothing.
     #[wasm_bindgen(js_name=setUserFeeIncrease)]
     pub fn set_user_fee_increase(&mut self, _user_fee_increase: u16) {}