### What problem does this PR solve?
Fix entity_types. Close#6287 and #6608
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Removed set_entity and set_relation to avoid accessing doc engine during
graph computation.
Introduced GraphChange to avoid writing unchanged chunks.
### Type of change
- [x] Performance Improvement
### What problem does this PR solve?
1. miss completion delimiter.
2. miss bracket process.
3. doc_ids return by update_graph is a set, and insert operation in
extract_community need a list.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)