CLN: replace %s syntax with .format in pandas.io

[makeajourney]

progress towards #16130

• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff

[codecov]

Codecov Report

Merging #24719 into master will increase coverage by <.01%.
The diff coverage is 82.08%.

@@            Coverage Diff             @@
##           master   #24719      +/-   ##
==========================================
+ Coverage   92.38%   92.38%   +<.01%     
==========================================
  Files         166      166              
  Lines       52321    52321              
==========================================
+ Hits        48337    48338       +1     
+ Misses       3984     3983       -1

Flag	Coverage Δ
#multiple	90.8% <25.37%> (ø)	⬆️
#single	43.06% <80.59%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/io/packers.py	88.21% <0%> (ø)	⬆️
pandas/io/sas/sas7bdat.py	91.16% <33.33%> (ø)	⬆️
pandas/io/pytables.py	92.31% <85.71%> (ø)	⬆️
pandas/util/testing.py	88.09% <0%> (+0.09%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d46d2a5...f3232f1. Read the comment docs.

[codecov]

Codecov Report

Merging #24719 into master will increase coverage by <.01%.
The diff coverage is 82.08%.

@@            Coverage Diff             @@
##           master   #24719      +/-   ##
==========================================
+ Coverage   92.38%   92.38%   +<.01%     
==========================================
  Files         166      166              
  Lines       52321    52321              
==========================================
+ Hits        48337    48338       +1     
+ Misses       3984     3983       -1

Flag	Coverage Δ
#multiple	90.8% <25.37%> (ø)	⬆️
#single	43.06% <80.59%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/io/packers.py	88.21% <0%> (ø)	⬆️
pandas/io/sas/sas7bdat.py	91.16% <33.33%> (ø)	⬆️
pandas/io/pytables.py	92.31% <85.71%> (ø)	⬆️
pandas/util/testing.py	88.09% <0%> (+0.09%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d46d2a5...f3232f1. Read the comment docs.

[jreback]

thanks!