Auto merge of #28965 - bluss:ptr-write-doc, r=huonw
Auto merge of #28965 - bluss:ptr-write-doc, r=huonw

core: Update the safety docs for core::ptr::write

Updated to reflect that not dropping a value is safe (but discouraged).

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