Bug 1610120 - Update SeaMonkey website for 2.53.1 Final release - flash plugin on legacy page. r=me

src/releases/legacy.en.html

@@ -26,8 +26,8 @@
 </div>
 
 <ul>
-
   <li>The last version supporting Windows XP/Server 2003 and Vista/Server 2008 was SeaMonkey 2.49.5.</li>
+  <li>The last version supporting plugins other than Flash on Windows and Linux was SeaMonkey 2.49.5.</li>
   <li>The last version with ALSA support on Linux was SeaMonkey 2.49.5.</li>
   <li>The last version supporting plugins other than Flash under macOS was SeaMonkey 2.49.4.</li>
   <li>The last version with gtk2 support on Linux was SeaMonkey 2.48.</li>