calculator: reset digits_after_dot for second number

[cedric-h]

oops, probably should've tested this a bit more thoroughly

Before: Click 9 then ., then 9, click +, then 5

Expected result: 14.9 Actual result: 9.95

[david-vanderson]

For stuff like this, you can directly commit it. Let me know if that's not working for you, or if you'd prefer to have me merge it.

[cedric-h]

It's committed! I'll save MRs for larger initiatives that warrant discussion, rather than quick hotfixes.