Tiny supportability nit: today we emit these log messages when adding a write block to an index:

```
[2022-03-22T19:43:26,897][INFO ][o.e.c.m.MetadataIndexStateService] [node_t1] adding block write to indices [[test-blocks/eLkrYpm_S3WNemfWpXrhPA]]
[2022-03-22T19:43:26,933][INFO ][o.e.c.m.MetadataIndexStateService] [node_t1] completed adding block write to indices [test-blocks]
```

This is kind of confusing, a `block write` sounds like we're writing a block of data. It's not clear that `write` is variable (we also say `block read`) or the name of a block setting. I think we should word this as `adding [index.blocks.write] block to indices` instead.
server/src/main/java/org/elasticsearch/cluster/metadata/MetadataIndexStateService.java
"close-indices",
                                                new CloseIndicesTask(task.request, blockedIndices, verifyResults, delegate2),
                                                ClusterStateTaskConfig.build(Priority.URGENT),
                                                closesExecutor
                                            );
                                        })
                                    )
                                );
                        }
                    });
                } catch (Exception e) {
                    taskContext.onFailure(e);
                }
            }
            return state;
        }
    }
    private record AddBlocksToCloseTask(CloseIndexClusterStateUpdateRequest request, ActionListener<CloseIndexResponse> listener)
        implements
            ClusterStateTaskListener {
        @Override
        public void onFailure(Exception e) {
            listener.onFailure(e);
        }
        @Override
        public void clusterStateProcessed(ClusterState oldState, ClusterState newState) {
            assert false : "not called";
        }
    }
    private class CloseIndicesExecutor implements ClusterStateTaskExecutor<CloseIndicesTask> {