public boolean getIsInsideDoc(Symbol fieldDefinition) {
        FieldIndexEntry entry = database.get(fieldDefinition);
        if (entry == null) return false;
        return entry.isInsideDoc;
    }
FieldIndex
For storing metadata about fields.
It is owned by a SchemaIndex, so there is a one-to-one correspondence
integration/schema-language-server/language-server/src/main/java/ai/vespa/schemals/index/FieldIndex.java