`parseModule` overload set should take the parser type as template parameter

[ghost]

Since we can make derived Parser classes.

updated functions would then be like:

/**
 * Params:
 *      parserConfig = a parser configuration.
 * Returns:
 *      The parsed module.
 */
Module parseModule(P = .Parser)(auto ref ParserConfig parserConfig)
{
    auto parser = new P();
    with (parserConfig)
    {
        parser.fileName = fileName;
        parser.tokens = tokens;
        parser.messageFunction = messageFunction;
        parser.messageDelegate = messageDelegate;
        parser.allocator = allocator;
    }
    Module mod = parser.parseModule();
    with (parserConfig)
    {
        if (warningCount !is null)
            *warningCount = parser.warningCount;
        if (errorCount !is null)
            *errorCount = parser.errorCount;
    }
    return mod;
}

/**
 * Params:
 *      tokens = The tokens parsed by dparse.lexer.
 *      fileName = The name of the file being parsed.
 *      allocator = A pointer to a rollback allocator.
 *      messageFuncOrDg = Either a function or a delegate that receives the parser messages.
 *      errorCount = An optional pointer to a variable receiving the error count.
 *      warningCount = An optional pointer to a variable receiving the warning count.
 * Returns:
 *      The parsed module.
 */
Module parseModule(P = .Parser,F)(const(Token)[] tokens, string fileName, RollbackAllocator* allocator,
    F messageFuncOrDg = null, uint* errorCount = null, uint* warningCount = null)
{
    static if (is(F))
    {
        static if (is(F : MessageFunction))
            return ParserConfig(tokens, fileName, allocator, messageFuncOrDg, null,
                errorCount, warningCount).parseModule();
        else static if (is(F : MessageDelegate))
            return ParserConfig(tokens, fileName, allocator, null, messageFuncOrDg,
                errorCount, warningCount).parseModule();
        else static assert(0, "F must be a MessageFunction or a MessageDelegate");
    }
    else
    {
        return ParserConfig(tokens, fileName, allocator, null, null, null, null).parseModule!P();
    }
} 

[WebFreak001]

seems like an easy change, can you make a PR to let CI run over it?