Add internal API typehints

[ankona]

Add typehints to internal APIs

[codecov]

Codecov Report

Merging #303 (fa9db5c) into develop (3f2dfa4) will decrease coverage by 0.31%.
The diff coverage is 90.70%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #303      +/-   ##
===========================================
- Coverage    87.85%   87.54%   -0.31%     
===========================================
  Files           59       59              
  Lines         3383     3461      +78     
===========================================
+ Hits          2972     3030      +58     
- Misses         411      431      +20     

Impacted Files	Coverage Δ
smartsim/_core/utils/redis.py	87.75% <ø> (ø)
smartsim/_core/launcher/colocated.py	92.22% <40.00%> (-1.04%)	⬇️
smartsim/ml/torch/data.py	83.92% <52.94%> (-11.73%)	⬇️
smartsim/_core/launcher/taskManager.py	81.03% <71.42%> (-1.43%)	⬇️
smartsim/_core/launcher/util/shell.py	83.72% <75.00%> (ø)
smartsim/_core/launcher/step/mpiStep.py	40.90% <77.77%> (+2.81%)	⬆️
smartsim/_core/launcher/stepMapping.py	74.41% <81.25%> (-0.59%)	⬇️
smartsim/_core/control/manifest.py	92.23% <87.50%> (-2.60%)	⬇️
smartsim/_core/launcher/step/localStep.py	88.57% <87.50%> (-1.76%)	⬇️
smartsim/ml/tf/data.py	84.09% <88.88%> (-1.28%)	⬇️
... and 26 more

[MattToast]

LGTM!!

[mellis13]

Great job -- LGTM!