public void addMatch(Function sourceFunction, Function targetFunction) {
		Set<Function> targets =
			sourceToTargetsMap.computeIfAbsent(sourceFunction, k -> new HashSet<>());
		targets.add(targetFunction);
		activeFunctions = new Duo<>(sourceFunction, targetFunction);
		fireModelDataChanged();
	}
Adds a new comparison to the model. If the sourceFunction already exists on the left side,
then the target function will be added to that specific function's right side functions. 
Otherwise, the source function will be added to the left side the given target as its only
right side function.
@param sourceFunction the left side function to add
@param targetFunction the right side function to add for that source function
Ghidra/Features/Base/src/main/java/ghidra/features/base/codecompare/model/MatchedFunctionComparisonModel.java