Link between tasks in Sunflower Gantt 0.7

Four links supported by sunflower Gantt
1. Complete-start
2. Start-start
3. Start-finish
4. Complete-complete

Data settings

Task 18 and 17 Completion-start (FS)
Task 19 and 18 start-start (SS)
Task 20 and 19 start-complete (SF)
Task 21 and 20 completed-finished (FF)

However, the Gantt diagram has a small bug.

tasks 18 and 17 are displayed correctly
Task 19 and task 18 show start-finish should show start-start ",
Task 20 and 19 charts show start-start, and "start-finish (SF)" should be displayed )"
Task 21 and task 20 show the error picture, and the "finished-finished (FF)" picture should be displayed )"

functions to be added:
click the link between tasks to display the link information between tasks.