id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
823930834,MDExOlB1bGxSZXF1ZXN0NTg2MjYxOTgz,5007,Rename map_blocks tasks.,2448579,closed,0,,,2,2021-03-07T14:27:58Z,2021-03-26T15:58:57Z,2021-03-26T15:58:56Z,MEMBER,,0,pydata/xarray/pulls/5007,"This makes it clearer which tasks are subsetting xarray objects, vs.
actually running the user provided function.

<!-- Feel free to remove check-list items aren't relevant to your change -->
- [ ] Tests added
- [x] Passes `pre-commit run --all-files`
- [ ] User visible changes (including notable bug fixes) are documented in `whats-new.rst`
- [ ] New functions/methods are listed in `api.rst`

```python
import dask

import xarray as xr

da = xr.DataArray(
    dask.array.zeros((10,), chunks=(3,)),
    dims=""dim_0"",
    coords={""a"": ((""dim_0"",), np.arange(10))},
    name=""data""
)


def func(a):
    return a.dim_0


da.map_blocks(func).data.visualize()
```

### before
![image](https://user-images.githubusercontent.com/2448579/110243177-85755780-7f16-11eb-96ab-2a020dcae21e.png)

### after

![image](https://user-images.githubusercontent.com/2448579/110243159-71315a80-7f16-11eb-9c61-90984957fc6e.png)

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