Balance sidebar Deref cycle check with main content

[jryans]

The Deref cycle checks added as part of #80653 were "unbalanced" in the sense
that the main content code path checks for cycles before descending, while the
sidebar checks after. Checking before is correct, so this changes the
sidebar path to match the main content path.

Fixes #81395

r? @GuillaumeGomez

[GuillaumeGomez]

Looks all good, thanks a lot! r=me once CI pass

[rust-log-analyzer]

The job mingw-check failed! Check out the build log: (web) (plain)

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

configure: rust.channel         := nightly
configure: rust.debug-assertions := True
configure: llvm.assertions      := True
configure: dist.missing-tools   := True
configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
configure: writing `config.toml` in current directory
configure: 
configure: run `python /checkout/x.py --help`
configure: 
---
skip untracked path cpu-usage.csv during rustfmt invocations
skip untracked path src/doc/book/ during rustfmt invocations
skip untracked path src/doc/rust-by-example/ during rustfmt invocations
skip untracked path src/llvm-project/ during rustfmt invocations
Diff in /checkout/src/librustdoc/html/render/mod.rs at line 3637:
             _ => None,
         })
         .expect("Expected associated type binding");
-    debug!("Render deref methods for {:#?}, target {:#?}",
-        impl_.inner_impl().for_,
-        target);
+    debug!("Render deref methods for {:#?}, target {:#?}", impl_.inner_impl().for_, target);
     let what =
         AssocItemRender::DerefFor { trait_: deref_type, type_: real_target, deref_mut_: deref_mut };
     if let Some(did) = target.def_id_full(cx.cache()) {
Running `"/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/rustfmt" "--config-path" "/checkout" "--edition" "2018" "--unstable-features" "--skip-children" "--check" "/checkout/src/librustdoc/html/render/mod.rs"` failed.
If you're running `tidy`, try again with `--bless`. Or, if you just want to format code, run `./x.py fmt` instead.
Build completed unsuccessfully in 0:00:19

[GuillaumeGomez]

Here we go!

@bors: r+

[bors]

📌 Commit a6fa92c has been approved by GuillaumeGomez

[JohnTitor]

@bors r-
This now has a merge conflict, @jryans could you resolve it?

[bors]

☔ The latest upstream changes (presumably #81398) made this pull request unmergeable. Please resolve the merge conflicts.

[jryans]

@GuillaumeGomez, can you re-review the rebase?

@rustbot label -S-waiting-on-author +S-waiting-on-review

[GuillaumeGomez]

Still looks good, thanks again!

@bors: r+

[bors]

📌 Commit 7e32178 has been approved by GuillaumeGomez