Update destructors.md

[Tbkhi]

Based on QA examples provided here: https://users.rust-lang.org/t/why-the-parameter-of-a-function-is-droped-afer-the-temporary-variable-in-return-of-the-function/106430/4

[Tbkhi]

CC: @mbrubeck

[Tbkhi]

CC; @ehuss

[Tbkhi]

Oops this will need to be fixed up.

[jdahlstrom]

First letter should be capitalized unless it's an identifier, for correctness and consistency with other Rust documentation (including this file). Ditto for all the other comments.

[traviscross]

We're discussing this in the rustdocs call. We're a bit unclear on the motivation for this change. If you could describe here in more detail what should be changed here, why, and why the change proposed is the right way to address it, that would be helpful.

Also, we note that the PR should be rebased and squashed.