Parser: Add cmd:visible, it's also a tag

parser.cpp

@@ -123,7 +123,7 @@ std::string Parser::parse(const PageDao &pagedao, UrlProvider &provider, const s
 	std::string result;
 	// we don't care about commands, but we nevertheless replace them with empty strings
 	std::regex tagfinder(
-		R"(\[(b|i|u|li||ul|ol|link|wikilink|h\d|cmd:rename|cmd:redirect|cmd:pagetitle|category|dynamic:postlist|dynamic:includepage|dynamic:getvar|dynamic:setvar)*?\]((\s|\S)*?)\[/\1])");
+		R"(\[(b|i|u|li||ul|ol|link|wikilink|h\d|cmd:visible|cmd:rename|cmd:redirect|cmd:pagetitle|category|dynamic:postlist|dynamic:includepage|dynamic:getvar|dynamic:setvar)*?\]((\s|\S)*?)\[/\1])");
 	result = utils::regex_callback_replacer(
 		tagfinder, content,
 		[&](std::smatch &match)