[clang-tidy] [PR50069] readability-braces-around-statements doesn't work well with [[likely]] [[unlikely]]

https://bugs.llvm.org/show_bug.cgi?id=50069

When clang-tidy sees:

```
if (true) [[unlikely]] {
    ...
}
```

It thinks the braces are missing and add them again.

```
if (true)  { [[unlikely]] {
    ...
  }
}
```

This revision aims to prevent that incorrect code generation

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D105479

clang-tools-extra/clang-tidy/readability/BracesAroundStatementsCheck.cpp

@@ -186,6 +186,10 @@ BracesAroundStatementsCheck::findRParenLoc(const IfOrWhileStmt *S,
 bool BracesAroundStatementsCheck::checkStmt(
     const MatchFinder::MatchResult &Result, const Stmt *S,
     SourceLocation InitialLoc, SourceLocation EndLocHint) {
+
+  while (const auto *AS = dyn_cast<AttributedStmt>(S))
+    S = AS->getSubStmt();
+
   // 1) If there's a corresponding "else" or "while", the check inserts "} "
   // right before that token.
   // 2) If there's a multi-line block comment starting on the same line after

clang-tools-extra/test/clang-tidy/checkers/readability-braces-around-statements-attributes.cpp

@@ -0,0 +1,24 @@
+// RUN: %check_clang_tidy  -std=c++20-or-later %s readability-braces-around-statements %t
+
+void test(bool b) {
+  if (b) {
+    return;
+  }
+  if (b) [[likely]] {
+    // CHECK-FIXES-NOT: if (b) { {{[[][[]}}likely{{[]][]]}} {
+    return;
+  }
+  if (b) [[unlikely]] {
+    // CHECK-FIXES-NOT: if (b) { {{[[][[]}}unlikely{{[]][]]}} {
+    return;
+  }
+
+  if (b) [[likely]]
+    // CHECK-FIXES: if (b) {{[[][[]}}likely{{[]][]]}} {
+    return;
+  // CHECK-FIXES: }
+  if (b) [[unlikely]]
+    // CHECK-FIXES: if (b) {{[[][[]}}unlikely{{[]][]]}} {
+    return;
+  // CHECK-FIXES: }
+}