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
this.indexMetadataVerifier = indexMetadataVerifier;
        this.indicesService = indicesService;
        this.shardLimitValidator = shardLimitValidator;
        this.client = client;
        this.threadPool = threadPool;
        this.activeShardsObserver = new ActiveShardsObserver(clusterService, threadPool);
        this.opensExecutor = new OpenIndicesExecutor();
        this.addBlocksToCloseExecutor = new AddBlocksToCloseExecutor();
        this.closesExecutor = new CloseIndicesExecutor();
        this.addBlocksExecutor = new AddBlocksExecutor();
        this.finalizeBlocksExecutor = new FinalizeBlocksExecutor();
    }
    /**
     * Closes one or more indices.
     *
     * Closing indices is a 3 steps process: it first adds a write block to every indices to close, then waits for the operations on shards
     * to be terminated and finally closes the indices by moving their state to CLOSE.
     */
    public void closeIndices(final CloseIndexClusterStateUpdateRequest request, final ActionListener<CloseIndexResponse> listener) {
        if (request.indices() == null || request.indices().length == 0) {
            throw new IllegalArgumentException("Index name is required");
        }
        clusterService.submitStateUpdateTask(
            "add-block-index-to-close " + Arrays.toString(request.indices()),
            new AddBlocksToCloseTask(request, listener),
            ClusterStateTaskConfig.build(Priority.URGENT, request.masterNodeTimeout()),
            this.addBlocksToCloseExecutor
        );
    }
    private class AddBlocksToCloseExecutor implements ClusterStateTaskExecutor<AddBlocksToCloseTask> {