Support SemanticConcept in icu::message2 for custom vocabulary #187
Description
SemanticConcept support should be added to icu::message2. This provides a way to perform custom inflections when the default inflection behavior is ambiguous, a language is unsupported by Unicode Inflection or precise inflection behavior is needed for custom terms are needed.
Support will need to hook into SemanticFeatureModel. There likely needs to be some sort of file format to handle this custom vocabulary that is fed into the SemanticFeatureModel.
Examples can be seen in SemanticConceptTest.cpp.