[Feature Request]: add reference line to plot difference

[zmirasilman]

Description

in paired ttest a line on the 0 would be helpfull

Purpose

emphasize if delta includes 0

Use-case

No response

Is your feature request related to a problem?

no

Is your feature request related to a JASP module?

T-Tests

Describe the solution you would like

add a horizontal line

Describe alternatives that you have considered

No response

Additional context

[EJWagenmakers]

This makes sense but should be optional, and I don't want to clutter the interface. So ideally this is made possible by extending the graph editor so that lines can be added to the plot.

[tomtomme]

this is now work in progress here: jasp-stats/jasp-desktop#6057
also closing, hence duplicate of #3115
please reopen if you disagree