refactor: mark modified_unknowns! as public

Author: AayushSabharwal

docs/src/API/System.md

@@ -211,4 +211,5 @@ ModelingToolkit.collect_scoped_vars!
 ModelingToolkit.collect_var_to_name!
 ModelingToolkit.collect_vars!
 ModelingToolkit.eqtype_supports_collect_vars
+ModelingToolkit.modified_unknowns!
 ```

src/ModelingToolkit.jl

@@ -343,7 +343,7 @@ export DynamicOptSolution
 @public VariableDescription, VariableInput, VariableIrreducible, VariableMisc
 @public VariableOutput, VariableStatePriority, VariableUnit, collect_scoped_vars!
 @public collect_var_to_name!, collect_vars!, eqtype_supports_collect_vars, hasdefault
-@public getdefault, setdefault, iscomplete, isparameter
+@public getdefault, setdefault, iscomplete, isparameter, modified_unknowns!
 
 for prop in [SYS_PROPS; [:continuous_events, :discrete_events]]
     getter = Symbol(:get_, prop)

src/problems/jumpproblem.jl

@@ -210,6 +210,13 @@ function get_variables!(dep, jump::MassActionJump, variables)
 end
 
 ### Functions to determine which unknowns are modified by a given jump
+
+"""
+    $(TYPEDSIGNATURES)
+
+Push to `munknowns` the variables modified by jump `jump`. `sts` is the list of unknowns of
+the system. Return the modified `munknowns`.
+"""
 function modified_unknowns!(munknowns, jump::Union{ConstantRateJump, VariableRateJump}, sts)
     for eq in jump.affect!
         st = eq.lhs