NFC ProgrammersManual fix

llvm-svn: 286645
diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst
index e4d3ddb..9c3b424 100644
--- a/llvm/docs/ProgrammersManual.rst
+++ b/llvm/docs/ProgrammersManual.rst
@@ -149,7 +149,7 @@
 
   .. code-block:: c++
 
-    if (AllocationInst *AI = dyn_cast<AllocationInst>(Val)) {
+    if (auto *AI = dyn_cast<AllocationInst>(Val)) {
       // ...
     }