Update dashboard message to reflect symbol and references

[suztomo]

Something like "106 symbols causing linkage errors on 516 references."

[elharo]

It's hard to think of something that doesn't exist as causing the error. Maybe

106 symbols not found when referenced by 516 call sites.

Still not quite right.

[suztomo]

It's not always "not found". There may be the other cases due to modifiers or binary-incompatible change.

"106 problems on 516 references"?

[elharo]

"on references" isn't clear. I think we need to move away from that.