Actually update the grammar of this sentence to reflect the removal of CellSPU.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170268 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 5159b48..2de4ebb 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -529,7 +529,7 @@
 
 Known problem areas include:
 
-#. MSP430, and XCore backends are experimental.
+#. The MSP430 and XCore backends are experimental.
 
 #. The integrated assembler, disassembler, and JIT is not supported by several
    targets.  If an integrated assembler is not supported, then a system