Revert "[clang][ThreadSafety] Fix code block syntax in ThreadSafetyAnalysis.rst (llvm#96494)"

This reverts commit 3402620.

Author: dmcardle

clang/docs/ThreadSafetyAnalysis.rst

@@ -464,7 +464,6 @@ on success and ``LockNotAcquired`` on failure, the analysis may fail to detect
 access to guarded data without holding the mutex because they are both non-zero.
 
 .. code-block:: c++
-
   // *** Beware: this code demonstrates incorrect usage. ***
 
   enum TrylockResult { LockAcquired = 1, LockNotAcquired = 2 };