rustdoc: don't give depreciation notes special handling in future edition

[lolbinarycat]

based on discussion in #149741

we're currently using pre-wrap here which forces us to do a bunch of other hacky weird stuff, but getting rid of all that would likely break some existing docs, so i'm proposing we do it across an edition.

r? @GuillaumeGomez

[rustbot]

Some changes occurred in HTML/CSS/JS.

cc @GuillaumeGomez, @lolbinarycat

[yotamofek]

Gonna let Guillaume r+, but looks good to me!

[rust-log-analyzer]

The job aarch64-gnu-llvm-20-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

failures:

---- html::markdown::tests::test_markdown_html_escape_new stdout ----

thread 'html::markdown::tests::test_markdown_html_escape_new' (58058) panicked at src/librustdoc/html/markdown/tests.rs:494:9:
assertion `left == right` failed: original: `Struct<'a, T>`
  left: "<span class=\"legacy-wrap\"><code>Struct&lt;'a, T&gt;</code></span>"
 right: "<p><code>Struct&lt;'a, T&gt;</code></p>"
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed::<alloc::string::String, alloc::string::String>

[GuillaumeGomez]

Just commented about this here. I'd personally just make the update without gating it behind next edition but seems like something worth discussing with the rest of the team.