8367724: Remove Trailing Return Types from undecided list

Reviewed-by: stefank, phubner

Author: Kim Barrett

doc/hotspot-style.html

@@ -1859,8 +1859,6 @@ <h3 id="stdlaunder"><code>std::launder()</code></h3>
 <h3 id="additional-undecided-features">Additional Undecided
 Features</h3>
 <ul>
-<li><p>Trailing return type syntax for functions (<a
-href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2541.htm">n2541</a>)</p></li>
 <li><p>Member initializers and aggregates (<a
 href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3653.html">n3653</a>)</p></li>
 <li><p>Rvalue references and move semantics</p></li>

doc/hotspot-style.md

@@ -1853,9 +1853,6 @@ See Object Lifetime: C++17 6.8/8, C++20 6.7.3/8
 
 ### Additional Undecided Features
 
-* Trailing return type syntax for functions
-([n2541](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2541.htm))
-
 * Member initializers and aggregates
 ([n3653](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3653.html))