Auto merge of #77850 - kornelski:resizedefault, r=dtolnay
Auto merge of #77850 - kornelski:resizedefault, r=dtolnay

Remove deprecated unstable Vec::resize_default

It's [been deprecated](https://github.com/rust-lang/rust/pull/57656) for 15 releases.

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