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
result.getKey(),
                            new IllegalStateException(
                                "verification of shards before closing " + index + " succeeded but index is being restored in the meantime"
                            )
                        )
                    );
                    logger.debug("verification of shards before closing {} succeeded but index is being restored in the meantime", index);
                    continue;
                }
                
                Set<Index> snapshottingIndices = SnapshotsService.snapshottingIndices(currentState, Set.of(index));
                if (snapshottingIndices.isEmpty() == false) {
                    closingResults.put(
                        result.getKey(),
                        new IndexResult(
                            result.getKey(),
                            new IllegalStateException(
                                "verification of shards before closing " + index + " succeeded but index is being snapshot in the meantime"
                            )
                        )
                    );
                    logger.debug("verification of shards before closing {} succeeded but index is being snapshot in the meantime", index);
                    continue;
                }
                blocks.removeIndexBlockWithId(index.getName(), INDEX_CLOSED_BLOCK_ID);
                blocks.addIndexBlock(index.getName(), INDEX_CLOSED_BLOCK);
                final IndexMetadata.Builder updatedMetadata = IndexMetadata.builder(indexMetadata).state(IndexMetadata.State.CLOSE);
                metadata.put(
                    updatedMetadata.timestampRange(IndexLongFieldRange.NO_SHARDS)
                        .settingsVersion(indexMetadata.getSettingsVersion() + 1)