[clang][bytecode][NFC] Surround Pointer diagram in \verbatim (#158550)

See if this fixes the documentation.
diff --git a/clang/lib/AST/ByteCode/Pointer.h b/clang/lib/AST/ByteCode/Pointer.h
index 49d701c..9e67374 100644
--- a/clang/lib/AST/ByteCode/Pointer.h
+++ b/clang/lib/AST/ByteCode/Pointer.h
@@ -75,7 +75,7 @@
 /// data the pointer decribes can be found at
 /// Pointee->rawData() + Pointer.Offset.
 ///
-///
+/// \verbatim
 /// Pointee                      Offset
 /// │                              │
 /// │                              │
@@ -87,6 +87,7 @@
 ///                      │
 ///                      │
 ///                     Base
+/// \endverbatim
 class Pointer {
 private:
   static constexpr unsigned PastEndMark = ~0u;