Description

[Doesn't quite fit any of the issue categories; this is more a suggestion than a bug.]
According to the documentation the excellent new XYChart doesn't have a way of showing series labels or legend. However the initial proposals for such a chart type did include such labels, and all graphing packages include this option.

Steps to reproduce

n/a

Screenshots

No response

Code Sample

No response

Setup

• Mermaid version: 10.8.0
• Browser and Version: n/a

Suggested Solutions

In the same way that a Y axis definition can include a title (y-axis "Revenue (in $)" ...) allow a name after the series name: line "Sales" [...].

Additional Context

No response