Remove 1.23.0 release notes entry on const_fn
Remove 1.23.0 release notes entry on const_fn

It doesn’t change anything for stable users in practice. See discussion in https://github.com/rust-lang/rust/pull/46148
graydon/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust