Rollup merge of #76721 - camelid:intra-doc-links-for-core-mem, r=jyn514
Rollup merge of #76721 - camelid:intra-doc-links-for-core-mem, r=jyn514

Use intra-doc links in `core::mem`

Part of #75080.

Last one for now!

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@rustbot modify labels: A-intra-doc-links T-doc

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