Better formatting for EMC value tooltip

Really big dmc values are hard to read due to the lack of commas.
Old: 123456789.312 (confusing)
New: 123,456,789.312 (much better)

Could also be done in a much simpler way like this:

event.toolTip.add("EMC: " + String.format("%,.3f", stack.getStackSize() * emcValue.getValue())):

But that would force the decimals to always be shown:
Old: 1
New: 1.000