chore: add log when ignoring target

src/burnchains/burnchain.rs

@@ -1215,13 +1215,19 @@ impl Burnchain {
         if let Some(target_block_height) = target_block_height_opt {
             // target_block_height is used as a hint, but could also be completely off
             // in certain situations. The current function is directly reading the
-            // headers and syncing with the bitcoin-node.
+            // headers and syncing with the bitcoin-node, and the interval of blocks
+            // to download computed here should be considered as our source of truth.
             if target_block_height > start_block && target_block_height < end_block {
                 debug!(
                     "Will download up to max burn block height {}",
                     target_block_height
                 );
                 end_block = target_block_height;
+            } else {
+                debug!(
+                    "Ignoring target block height {} considered as irrelevant",
+                    target_block_height
+                );
             }
         }