Rollup merge of #107078 - ehuss:invalid_doc_attributes-docs, r=jackh726

Update wording of invalid_doc_attributes docs.

There was a typo in the original docs for `invalid_doc_attributes`. I felt it could use a little rewording to try to clarify the reasoning for the lint. Also, this adds the future-incompatible notice.

diff --cc compiler/rustc_lint_defs/src/builtin.rs
Simple merge