Fix grammar issues 12810, 13310, 13329

[Issue 12810](https://issues.dlang.org/show_bug.cgi?id=12810) - PrimaryExpression grammar does not allow type constructors
[Issue 13310](https://issues.dlang.org/show_bug.cgi?id=13310) - Old style multiple alias declaration not documented
[Issue 13329](https://issues.dlang.org/show_bug.cgi?id=13329) - AutoDeclarationX grammar lists '=' token and template parameters in the wrong order