Officially support mailto links for "issues" field

[SoniEx2]

trafficstars

Is your feature request related to a problem? Please describe.

We don't have a real issue tracker for our mods.

Describe the solution you'd like

Email is old-fashioned but it still generally works. We should be able to just use it for "issues" field.

Describe alternatives you've considered

There are URL redirectors around which support mailto but it should really be built-in instead.

Additional context

N/A