Mark -parallel pass as `experimental'


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19858 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index 660b363..a1b6dd5 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -208,7 +208,7 @@
 <ul>
 <li>The following passes are incomplete or buggy, and may be removed in future
     releases: <tt>-pgmdep, -memdep, -ipmodref, -cee, -branch-combine,
-    -instloops, -paths, -pre</tt></li>
+    -instloops, -parallel, -paths, -pre</tt></li>
 <li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
     be used to step through programs and inspect the stack.</li>
 <li>The "iterative scan" register allocator (enabled with -regalloc=iterativescan)