docs(nns): Added a TODO with Jira ticket ID about the demise of refresh neuron flags. (dfinity#3783)

This just adds a small comment.

Author: daniel-wong-dfinity-org

rs/nns/governance/src/lib.rs

@@ -195,9 +195,9 @@ pub const DEFAULT_VOTING_POWER_REFRESHED_TIMESTAMP_SECONDS: u64 = 1725148800;
 // leave this here indefinitely, but it will just be clutter after a modest
 // amount of time.
 thread_local! {
-
+    // TODO(NNS1-3601): Delete these (assuming all goes well, ofc) in mid March.
+    // There is already a draft PR for this.
     static IS_VOTING_POWER_ADJUSTMENT_ENABLED: Cell<bool> = const { Cell::new(true) };
-
     static IS_PRUNE_FOLLOWING_ENABLED: Cell<bool> = const { Cell::new(true) };
 
     static ALLOW_ACTIVE_NEURONS_IN_STABLE_MEMORY: Cell<bool> = const { Cell::new(true) };