[libc++][NFC] Mark LWG issue 2899 as not complete.

Commit 59e2630 accidentally
marked this LWG issue as complete but it has not yet been
implemented. D66262 fixes this issue.

libcxx/www/cxx2a_status.html

@@ -420,7 +420,7 @@ <h3>Library Working group Issues Status</h3>
 	<tr><td><a href="https://wg21.link/LWG3182">3182</a></td><td>Specification of <tt>Same</tt> could be clearer</td><td>Kona</td><td></td></tr>
 
 	<tr><td></td><td></td><td></td><td></td></tr>
-	<tr><td><a href="https://wg21.link/LWG2899">2899</a></td><td><tt>is_(nothrow_)move_constructible</tt> and <tt>tuple</tt>, <tt>optional</tt> and <tt>unique_ptr</tt></td><td>Cologne</td><td>Complete</td></tr>
+	<tr><td><a href="https://wg21.link/LWG2899">2899</a></td><td><tt>is_(nothrow_)move_constructible</tt> and <tt>tuple</tt>, <tt>optional</tt> and <tt>unique_ptr</tt></td><td>Cologne</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3055">3055</a></td><td><tt>path::operator+=(<i>single-character</i>)</tt> misspecified</td><td>Cologne</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3158">3158</a></td><td><tt>tuple(allocator_arg_t, const Alloc&amp;)</tt> should be conditionally explicit</td><td>Cologne</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3169">3169</a></td><td><tt>ranges</tt> permutation generators discard useful information</td><td>Cologne</td><td></td></tr>