Implement TryFrom explicitly for infallible numeric conversions.
Implement TryFrom explicitly for infallible numeric conversions.

See https://github.com/rust-lang/rust/pull/44174#discussion_r135982787

GBGamer/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust