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
indicesToClose.add(index);
            } else {
                logger.debug("index {} is already closed, ignoring", index);
                assert currentState.blocks().hasIndexBlock(index.getName(), INDEX_CLOSED_BLOCK);
            }
        }
        if (indicesToClose.isEmpty()) {
            return currentState;
        }
        
        Set<Index> restoringIndices = RestoreService.restoringIndices(currentState, indicesToClose);
        if (restoringIndices.isEmpty() == false) {
            throw new IllegalArgumentException("Cannot close indices that are being restored: " + restoringIndices);
        }
        
        Set<Index> snapshottingIndices = SnapshotsService.snapshottingIndices(currentState, indicesToClose);
        if (snapshottingIndices.isEmpty() == false) {
            throw new SnapshotInProgressException(
                "Cannot close indices that are being snapshotted: "
                    + snapshottingIndices
                    + ". Try again after snapshot finishes or cancel the currently running snapshot."
            );
        }
        final ClusterBlocks.Builder blocks = ClusterBlocks.builder(currentState.blocks());
        for (Index index : indicesToClose) {
            ClusterBlock indexBlock = null;
            final Set<ClusterBlock> clusterBlocks = currentState.blocks().indices().get(index.getName());
            if (clusterBlocks != null) {
                for (ClusterBlock clusterBlock : clusterBlocks) {
                    if (clusterBlock.id() == INDEX_CLOSED_BLOCK_ID) {