add a comment about why reset

crates/storage/libmdbx-rs/src/txn_manager.rs

@@ -204,7 +204,15 @@ mod read_transactions {
                                 (
                                     txn_ptr,
                                     duration,
-                                    // Abort the transaction
+                                    // Abort the transaction.
+                                    //
+                                    // We use `mdbx_txn_reset` instead of `mdbx_txn_abort` here to
+                                    // prevent MDBX from reusing the pointer of the aborted
+                                    // tranasction for new read-only transactions. This is
+                                    // important because we store the pointer in the `active` list
+                                    // and we don't want to accidentally abort a new transaction.
+                                    //
+                                    // See https://erthink.github.io/libmdbx/group__c__transactions.html#gae9f34737fe60b0ba538d5a09b6a25c8d for more info.
                                     mdbx_result(unsafe { ffi::mdbx_txn_reset(txn_ptr) }),
                                 )
                             });