Hello B.,
A possible workaround, as mentioned on /11603:
Adapted from: https://forum.plantuml.net/9142/how-to-explain-used-line-types-associations-in-a-diagram
and from this answer : https://forum.plantuml.net/9142/how-to-explain-used-line-types-associations-in-a-diagram?show=9149#c9149
→ "You can create an image and after use it on all your diagrams [or legend table]"
Here is a possible example:
@startuml
legend
| # | Embedded Puml| Code | Img. |
| 1 | {{\na->b:test 1\n}} | ""a->b:test 1"" | <img:http://www.plantuml.com/plantuml/png/IzIrIx8gIIqkKJ040000> |
| 2 | {{\na->b:test 2\n}} | ""a->b:test 2"" | <img:http://www.plantuml.com/plantuml/png/IzIrIx8gIIqkKJ3Y0W00> |
endlegend
@enduml
[Code on PlantUML online server]
If that can help,
Regards,
Th.