CLN: replace %s syntax with .format in pandas.tseries
Progress towards #16130

- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Replaced `%s` syntax with `.format` in pandas.tseries. Additionally, made some of the existing positional `.format` code more explicit.

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=h1) Report
> Merging [#17290](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/34c4ffd7c454848311f71e6869b5cad4bc132449?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `84.74%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17290/graphs/tree.svg?token=eZ4WkYLtcO&width=650&src=pr&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17290      +/-   ##
==========================================
- Coverage      91%   90.99%   -0.02%     
==========================================
  Files         162      162              
  Lines       49547    49563      +16     
==========================================
+ Hits        45092    45098       +6     
- Misses       4455     4465      +10
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.77% <84.74%> (ø)` | :arrow_up: |
| #single | `40.24% <8.47%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/holiday.py](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvaG9saWRheS5weQ==) | `93.1% <0%> (ø)` | :arrow_up: |
| [pandas/tseries/frequencies.py](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvZnJlcXVlbmNpZXMucHk=) | `96.51% <83.33%> (-0.16%)` | :arrow_down: |
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `97.14% <87.5%> (+0.01%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.72% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=footer). Last update [34c4ffd...bef8d63](https://codecov.io/gh/pandas-dev/pandas/pull/17290?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 actually very happy to take fixes we have more than enough issues to go around. thanks @jschendel 