Correctly handle comments in attributes in doctests source code

[GuillaumeGomez]

Fixes #134221.

The problem was that attributes are "inlined" (backlines are stripped), then when there is an inline comment inside it, the attribute is never considered valid (since unclosed). Fix was to simply put back backlines in case it's a multiline attribute.

r? @notriddle

[GuillaumeGomez]

Forgot to set only one test thread to prevent having fuzzy sorting...

[GuillaumeGomez]

And to replace stdout for time too...

[rust-log-analyzer]

The job x86_64-gnu-llvm-18 failed! Check out the build log: (web) (plain)

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#17 exporting to docker image format
#17 sending tarball 29.1s done
#17 DONE 34.5s
##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-18]
debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured.
---
sccache: Starting the server...
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-18', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--enable-new-symbol-mangling']
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-18/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
  Downloaded boml v0.3.1
   Compiling boml v0.3.1
   Compiling y v0.1.0 (/checkout/compiler/rustc_codegen_gcc/build_system)
    Finished `release` profile [optimized] target(s) in 4.04s
     Running `/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-codegen/x86_64-unknown-linux-gnu/release/y test --use-system-gcc --use-backend gcc --out-dir /checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc --release --mini-tests --std-tests`
Using system GCC
[BUILD] example
[AOT] mini_core_hello_world
/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc/mini_core_hello_world
abc
---

failures:

---- [ui] tests/rustdoc-ui/doctest/comment-in-attr-134221.rs stdout ----
Saved the actual stdout to "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-ui/doctest/comment-in-attr-134221/comment-in-attr-134221.stdout"

1 
2 running 2 tests
- test $DIR/doctest/comment-in-attr-134221.rs - (line 11) ... FAILED
- test $DIR/doctest/comment-in-attr-134221.rs - (line 11) ... FAILED
- test $DIR/doctest/comment-in-attr-134221.rs - (line 17) ... FAILED
+ test $DIR/comment-in-attr-134221.rs - (line 11) ... FAILED
+ test $DIR/comment-in-attr-134221.rs - (line 17) ... FAILED
5 
6 failures:
7 

- ---- $DIR/doctest/comment-in-attr-134221.rs - (line 11) stdout ----
+ ---- $DIR/comment-in-attr-134221.rs - (line 11) stdout ----
9 error[E0635]: unknown feature `foo`
-   --> $DIR/doctest/comment-in-attr-134221.rs:$LINE:$COL
+   --> $DIR/comment-in-attr-134221.rs:$LINE:$COL
12 LL |   foo, //
13    |   ^^^

16 
16 
17 For more information about this error, try `rustc --explain E0635`.
18 Couldn't compile the test.
- ---- $DIR/doctest/comment-in-attr-134221.rs - (line 17) stdout ----
+ ---- $DIR/comment-in-attr-134221.rs - (line 17) stdout ----
20 error[E0635]: unknown feature `foo`
-   --> $DIR/doctest/comment-in-attr-134221.rs:$LINE:$COL
+   --> $DIR/comment-in-attr-134221.rs:$LINE:$COL
23 LL |   foo,
24    |   ^^^

29 Couldn't compile the test.
---
- ---- /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs - (line 17) stdout ----
-   --> /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs:18:3
-     /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs - (line 11)
-     /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs - (line 17)
+ test $DIR/comment-in-attr-134221.rs - (line 11) ... FAILED
+ test $DIR/comment-in-attr-134221.rs - (line 17) ... FAILED
+ ---- $DIR/comment-in-attr-134221.rs - (line 11) stdout ----
+   --> $DIR/comment-in-attr-134221.rs:$LINE:$COL
+ ---- $DIR/comment-in-attr-134221.rs - (line 17) stdout ----
+   --> $DIR/comment-in-attr-134221.rs:$LINE:$COL
+     $DIR/comment-in-attr-134221.rs - (line 11)
+     $DIR/comment-in-attr-134221.rs - (line 17)

The actual stdout differed from the expected stdout.
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args doctest/comment-in-attr-134221.rs`
To only update this specific test, also pass `--test-args doctest/comment-in-attr-134221.rs`

error: 1 errors occurred comparing output.
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustdoc" "/checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2" "--target=x86_64-unknown-linux-gnu" "--check-cfg" "cfg(FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-ui/doctest/comment-in-attr-134221" "-A" "internal_features" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--test" "--test-args" "--test-threads=1"

running 2 tests
test /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs - (line 11) ... FAILED
test /checkout/tests/rustdoc-ui/doctest/comment-in-attr-134221.rs - (line 17) ... FAILED

[cyrgani]

Does this also fix that

//! ```rust
//! #![
//! ```

is incorrectly treated as a sucessful test?