Numeric trait impls for i64 and u64 missing

[nhoyle]

I had been using Formatter::fmt and casting my integer types to f64 to use it. I just did a cargo update, got told fmt was deprecated and to use fmt2. Saw that it supports any Numeric type. I thought "Great! I can use my integer types directly now, and avoid the cast I didn't want." I took the cast off of a u64 and passed it into fmt2 and was very surprised when the trait bound failed. As far as I can tell, after looking, it appears that there are Numeric trait impls for signed and unsigned 8, 16, 32, and 128 bit integers. Is there a reason we skipped 64-bit? It's the native register size on x86_64 architecture, as well as being a very useful size. I think this is simply missing, and should be present.

[kurtlawrence]

Whoops, I missed the inclusion of [i,u]64 in the macro 😵‍💫.

I've got a fix in the works and will get a release out soon, thanks for filing the issue.

[nhoyle]

I updated to the new crate version, and removed my casts, to use u64 types directly. Compiled fine, and a subsequent test run of the program in question ran as expected. Thanks for the quick turnaround on this issue!