mention that C style for loops are deprecated.

Author: lattner

CHANGELOG.md

@@ -1,5 +1,11 @@
 Latest
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+
+* The "C style for loop", which is spelled for (init; comparison; increment){}"
+  has been deprecated and is slated for removal in Swift 3.0.  See
+  [SE-0007](https://github.com/apple/swift-evolution/blob/master/proposals/0007-remove-c-style-for-loops.md)
+  for more information.
+
 * Three new doc comment fields, namely `- keyword:`, `- recommended:`
   and `- recommendedover:`, allow Swift users to cooperate with code
   completion engine to deliver more effective code completion results.