private void setSeparatorString(boolean bolding, SeparatorFieldPart f) {
        if (bolding)
            f.setContent(separatorTag);
        else
            f.setContent(ELLIPSIS);
    }
This converts the backend binary highlighting of each item in an array of string field,
and creates a new field that replaces the original.
container-search/src/main/java/com/yahoo/prelude/searcher/JuniperSearcher.java