Update Optimal Control Example Documentation

[wenwen0231]

Summary
Fix documentation typos in optimal control examples & add unit tests that check the output results match expected values within a certain tolerance.

Closing issues
Fixes issue #379

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.67%. Comparing base (5915743) to head (6d96753).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #380   +/-   ##
=======================================
  Coverage   99.67%   99.67%           
=======================================
  Files          35       35           
  Lines        6760     6760           
=======================================
  Hits         6738     6738           
  Misses         22       22           

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[pulsipher]

Thanks for this, the doc failure is due to link check failures that should go away when we run it again. To make the tests more robust, please change to tolerance to 1e-6.