"Locked by another running instance of Minecraft" lacks punctuation

The bug:

"Locked by another running instance of Minecraft" lacks punctuation. I would expect it to have at least a period, to be consistent with similar messages.

A similar message would be "Don't forget to back up this world before you load it in this snapshot." which has a period.

Expected Result:

It would have a period at the end.

Observed Result:

No punctuation is present.