Doxygen: update search help.

Doxyfile-mcss

@@ -106,7 +106,7 @@ HTML_EXTRA_STYLESHEET = \
 
 ##! M_PAGE_FINE_PRINT = "<p>Magnum docs. Part of the <a href="https://magnum.graphics/">Magnum project</a>, copyright © <a href="http://mosra.cz/">Vladimír Vondruš</a> and contributors, 2010&ndash;2018.<br />Generated by <a href="https://doxygen.org/">Doxygen</a> {doxygen_version} and <a href="https://mcss.mosra.cz/">m.css</a>. Contact the team via <a href="https://github.com/mosra/magnum">GitHub</a>, <a href="https://gitter.im/mosra/magnum">Gitter</a>, <a href="mailto:info@magnum.graphics">e-mail</a> or <a href="https://twitter.com/czmosra">Twitter</a>.</p>"
 
-##! M_SEARCH_HELP = "Search for symbols, directories, files, pages, OpenGL/GLSL and OpenAL APIs. You can omit any prefix from the symbol or file path; adding a <code>:</code> or <code>/</code> suffix lists all members of given symbol or directory. Navigate through the list using <span class="m-label m-dim">&darr;</span> and <span class="m-label m-dim">&uarr;</span>, press <span class="m-label m-dim">Enter</span> to go."
+##! M_SEARCH_HELP = "<p class="m-noindent">Search for symbols, directories, files, pages, OpenGL, GLSL, Vulkan and OpenAL APIs. You can omit any prefix from the symbol or file path; adding a <code>:</code> or <code>/</code> suffix lists all members of given symbol or directory.</p> <p class="m-noindent">Use <span class="m-label m-dim">&darr;</span> / <span class="m-label m-dim">&uarr;</span> to navigate through the list, <span class="m-label m-dim">Enter</span> to go. <span class="m-label m-dim">Tab</span> autocompletes common prefix, you can copy a link to the result using <span class="m-label m-dim">⌘</span> <span class="m-label m-dim">L</span> while <span class="m-label m-dim">⌘</span> <span class="m-label m-dim">M</span> produces a Markdown link.</p>"
 
 ##! M_FAVICON = doc/favicon.ico