[C99] Claim conformance to "more precise aliasing rules via effective type"

We don't have a document number to check our behavior against, but the
document title makes it clear that this is related to optimization
behavior, which doesn't require Clang to change.

Author: AaronBallman

clang/www/c_status.html

@@ -110,7 +110,7 @@ <h2 id="c99">C99 implementation status</h2>
     <tr>
       <td>more precise aliasing rules via effective type</td>
       <td>Unknown</td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Yes</td>
     </tr>
     <tr>
       <td>restricted pointers</td>