Miscellaneous fixes / cleanup

[speth]

Changes proposed in this pull request

This PR fixes a few small things that didn't seem worth independent PRs.

• Match Sundials integer type in some functions (see discussion in Cantera 2.6.0: Multiple test failures if built with Lapack support and with Sundials 6.2.0 #1419, though I don't think this is a fix for that issue)
• Fix handling of mechanism validation when minimal Python module is installed (validation needs to just be skipped, not cause an error)
• Describe Peng-Robinson input parameters in YAML API docs
• Deprecate Kinetics::surfacePhaseIndex in favor of Kinetics::reactionPhaseIndex
• Deprecate unused ThermoPhase::getChemPotentials_RT method
• Remove obsolete "friend" declaration referencing nonexistent SolveSS class
• Remove references to "ASCII" input files
• Fix various spelling errors

Checklist

• The pull request includes a clear description of this code change
• Commit messages have short titles and reference relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• Style & formatting of contributed code follows contributing guidelines
• The pull request is ready for review

[codecov]

Codecov Report

Merging #1427 (ad3a627) into main (39d5f33) will increase coverage by 0.00%.
The diff coverage is 47.82%.

@@           Coverage Diff           @@
##             main    #1427   +/-   ##
=======================================
  Coverage   70.73%   70.73%           
=======================================
  Files         378      378           
  Lines       55131    55134    +3     
  Branches    18158    18164    +6     
=======================================
+ Hits        38995    38999    +4     
  Misses      13626    13626           
+ Partials     2510     2509    -1     

Impacted Files	Coverage Δ
include/cantera/cython/funcWrapper.h	74.56% <ø> (ø)
include/cantera/kinetics/BlowersMaselRate.h	95.34% <ø> (ø)
include/cantera/kinetics/ImplicitSurfChem.h	100.00% <ø> (ø)
include/cantera/kinetics/InterfaceRate.h	81.92% <ø> (ø)
include/cantera/kinetics/Kinetics.h	32.59% <ø> (-0.99%)	⬇️
include/cantera/kinetics/PlogRate.h	100.00% <ø> (ø)
include/cantera/oneD/Domain1D.h	82.35% <ø> (ø)
include/cantera/oneD/StFlow.h	95.53% <ø> (ø)
include/cantera/thermo/HMWSoln.h	50.00% <ø> (ø)
include/cantera/thermo/IdealGasPhase.h	92.30% <ø> (ø)
... and 34 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[ischoegl]

Likewise, thanks. Changes look goo do me!