CLN: replace %s syntax with .format in missing.py, nanops.py, ops.py
Progress towards #16130
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Replaced `%s` syntax with `.format` in `missing.py`, `nanops.py`, `ops.py`. Additionally, made some of the existing positional `.format` code more explicit.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=h1) Report
> Merging [#17322](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/66ec5f3e616f6449ef2c88401042cf2a282234d7?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `78.94%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17322/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17322      +/-   ##
==========================================
- Coverage   91.03%   91.01%   -0.02%     
==========================================
  Files         162      162              
  Lines       49558    49564       +6     
==========================================
- Hits        45117    45113       -4     
- Misses       4441     4451      +10
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.8% <78.94%> (-0.01%)` | :arrow_down: |
| #single | `40.24% <13.15%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/nanops.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbmFub3BzLnB5) | `97.65% <100%> (ø)` | :arrow_up: |
| [pandas/core/missing.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbWlzc2luZy5weQ==) | `84.3% <58.82%> (-0.07%)` | :arrow_down: |
| [pandas/core/ops.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvb3BzLnB5) | `91.86% <94.44%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?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/17322?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/17322?src=pr&el=footer). Last update [66ec5f3...a6910d2](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=h1) Report
> Merging [#17322](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/66ec5f3e616f6449ef2c88401042cf2a282234d7?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `78.94%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17322/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17322      +/-   ##
==========================================
- Coverage   91.03%   91.01%   -0.02%     
==========================================
  Files         162      162              
  Lines       49558    49564       +6     
==========================================
- Hits        45117    45113       -4     
- Misses       4441     4451      +10
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.8% <78.94%> (-0.01%)` | :arrow_down: |
| #single | `40.24% <13.15%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/nanops.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbmFub3BzLnB5) | `97.65% <100%> (ø)` | :arrow_up: |
| [pandas/core/missing.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbWlzc2luZy5weQ==) | `84.3% <58.82%> (-0.07%)` | :arrow_down: |
| [pandas/core/ops.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvb3BzLnB5) | `91.86% <94.44%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17322?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/17322?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/17322?src=pr&el=footer). Last update [66ec5f3...a6910d2](https://codecov.io/gh/pandas-dev/pandas/pull/17322?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Thanks