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
indexBlock = clusterBlock;
                        break;
                    }
                }
            }
            if (indexBlock == null) {
                
                indexBlock = createIndexClosingBlock();
            }
            assert Strings.hasLength(indexBlock.uuid()) : "Closing block should have a UUID";
            blocks.addIndexBlock(index.getName(), indexBlock);
            blockedIndices.put(index, indexBlock);
        }
        logger.info(() -> format("closing indices %s", blockedIndices.keySet().stream().map(Object::toString).collect(joining(","))));
        return ClusterState.builder(currentState).blocks(blocks).build();
    }
    /**
     * Updates the cluster state for the given indices with the given index block,
     * and also returns the updated indices (and their blocks) in a map.
     * @param indices The indices to add blocks to if needed
     * @param currentState The current cluster state
     * @param block The type of block to add
     * @return a tuple of the updated cluster state, as well as the blocks that got added
     */
    private static Tuple<ClusterState, Map<Index, ClusterBlock>> addIndexBlock(
        final Index[] indices,
        final ClusterState currentState,
        final APIBlock block
    ) {