* fix: nocache feature code rot
The MBChunk::snapshot code when using the "nocache" option no longer
compiles - this commit updates it to match the not(nocache) code.
* build: use updated broken_intra_doc_links name
The broken_intra_doc_links lint was renamed
rustdoc::broken_intra_doc_links
https://doc.rust-lang.org/rustdoc/lints.html