CLN: replace %s syntax with .format in io
Progress toward issue #16130. Converted old string formatting to new string formatting in io/html.py, io/excel.py, msgpack/_packer.pyx, msgpack/_unpacker.pyx, clipboard/exceptions.py, json/json.py, json/normalize.py, sas/sas.pyx


# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=h1) Report
> Merging [#17660](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/6da85b30d989855fe2a1f5d1323189f0fc639e60?src=pr&el=desc) will **decrease** coverage by `0.02%`.
> The diff coverage is `38.88%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17660/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17660      +/-   ##
==========================================
- Coverage   91.26%   91.24%   -0.03%     
==========================================
  Files         163      163              
  Lines       49806    49806              
==========================================
- Hits        45455    45445      -10     
- Misses       4351     4361      +10
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.04% <38.88%> (-0.01%)` | :arrow_down: |
| #single | `40.3% <0%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/json/json.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2pzb24vanNvbi5weQ==) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/io/clipboard/exceptions.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9leGNlcHRpb25zLnB5) | `71.42% <0%> (ø)` | :arrow_up: |
| [pandas/io/json/normalize.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2pzb24vbm9ybWFsaXplLnB5) | `96.93% <100%> (ø)` | :arrow_up: |
| [pandas/io/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2h0bWwucHk=) | `84.85% <28.57%> (ø)` | :arrow_up: |
| [pandas/io/excel.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2V4Y2VsLnB5) | `80.37% <45%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.73% <0%> (-0.1%)` | :arrow_down: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `95.44% <0%> (-0.1%)` | :arrow_down: |

------

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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=footer). Last update [6da85b3...adf47f0](https://codecov.io/gh/pandas-dev/pandas/pull/17660?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks!