optimize/improve parser regex

TODO

@@ -1,9 +0,0 @@
-search: allow all chars (filter sqlite match syntax)
-add permission indicating whether user can see "invisible" pages in lists
-diff
-Redirection
-UI for permission system.
-user administration
-user registration
-more caching
-not all config values take effect yet.

parser.cpp

@@ -120,7 +120,8 @@ std::string Parser::processLink(const PageDao &pageDao, UrlProvider &urlProvider
 std::string Parser::parse(const PageDao &pagedao, UrlProvider &provider, std::string content) const
 {
 	std::string result;
-	std::regex tagfinder(R"(\[(.*?)\]((\s|\S)*?)\[/\1\])");
+	// we don't care about commands, but we nevertheless replace them with empty strings
+	std::regex tagfinder(R"(\[(b|i|u|li||ul|ol|link|wikilink|h\d|cmd:rename|cmd:redirect)*?\]((\s|\S)*?)\[/\1])");
 	result = utils::regex_callback_replacer(tagfinder, content, [&](std::smatch &match) {
 		std::string tag = match.str(1);
 		std::string content = match.str(2);