[clang][NFC] Fix typo in the name of a note

Summary:
r306722 introduced a new note called note_silence_unligned_allocation_unavailable
where I believe what was meant is note_silence_aligned_allocation_unavailable.

Reviewers: ahatanak

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51043

llvm-svn: 340288
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 4b208ff..1831430 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -1744,7 +1744,7 @@
     S.Diag(Loc, diag::err_aligned_allocation_unavailable)
         << IsDelete << FD.getType().getAsString() << OSName
         << alignedAllocMinVersion(T.getOS()).getAsString();
-    S.Diag(Loc, diag::note_silence_unligned_allocation_unavailable);
+    S.Diag(Loc, diag::note_silence_aligned_allocation_unavailable);
   }
 }