fix(mfusg): fix multiple bugs

[wpbonelli]

Fix what look like copy/paste errors in mfusgrch.py, missing leading f in front of format strings in several places, and a bad format specifier

[codecov]

Codecov Report

❌ Patch coverage is 14.28571% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.5%. Comparing base (556c088) to head (c89439c).
⚠️ Report is 173 commits behind head on develop.

Files with missing lines	Patch %	Lines
flopy/mfusg/mfusgoc.py	0.0%	5 Missing ⚠️
flopy/mfusg/mfusgrch.py	50.0%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2770      +/-   ##
===========================================
+ Coverage     55.5%    72.5%   +17.0%     
===========================================
  Files          644      677      +33     
  Lines       124135   132714    +8579     
===========================================
+ Hits         68947    96344   +27397     
+ Misses       55188    36370   -18818     

Files with missing lines	Coverage Δ
flopy/mfusg/mfusgrch.py	77.9% <50.0%> (ø)
flopy/mfusg/mfusgoc.py	59.9% <0.0%> (ø)

... and 578 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[mwtoews]

Looks good, but the test should be moved to where it is more relevant.

[wpbonelli]

thanks @mwtoews nice catch