Update cpp/rat.cpp

Co-authored-by: Alex H. Room <69592136+alexhroom@users.noreply.github.com>

Author: StephenNneji

cpp/rat.cpp

@@ -621,7 +621,7 @@ priors : RATapi.rat_core.Priors
 Returns
 -------
 out_problem_def : Rat.rat_core.ProblemDefinition
-    The problem input with the updated fit values.
+    The project input with the updated fit values.
 results : Rat.rat_core.OutputResult
     The results from a RAT calculation.
 bayes_result : Rat.rat_core.BayesResults