Allow letters in commands that take ruby amounts

For example, you could use the command /pay <user> 5k to pay someone 5,000 rubies, instead of having to type out the 5000. This would also ideally work with /auction. Specifically, these commands should allow “K” and “M” to stand for thousand and million, as well as allowing fractional amounts of those quantifiers (such as “1.25M” for 1,250,000).

Currently, having to type out the full number means the command is prone to typos, such as adding or forgetting a zero. For example, in the example above, it is possible to accidentally type 50000 instead of 5000, leading to you accidentally sending 10x as many rubies as intended, with no way to get them back.