swift

669d00ec - StdlibRef: Sequence.withContiguousStorageIfAvailable(_:) abstract needs a rewrite (#40334) (#40572)

StdlibRef: Sequence.withContiguousStorageIfAvailable(_:) abstract needs a rewrite (#40334) (#40572) * First draft of incorporating material from #38891 * Apply suggestions from Alex's review Co-authored-by: Alex Martini <amartini@apple.com> * Rephrase suggested by Alex. * Remove redundancy re: "don't replace buffer". * Apply changes from editorial review. * Apply Sequence edits (a3a3ff1) to MutableCollect'n * Remove errant space. Co-authored-by: Guillaume Lessard <glessard@users.noreply.github.com> Co-authored-by: Chris Adamson <cadamson@apple.com> Co-authored-by: Alex Martini <amartini@apple.com> Co-authored-by: Guillaume Lessard <glessard@users.noreply.github.com> (cherry picked from commit 59559ca0ce668b0240bcb2a91f874922a8eba2d7)