syntax: Allow semi tokens after macro ty/path

syntax: Allow semi tokens after macro ty/path

This commit expands the follow set of the `ty` and `path` macro fragments to
include the semicolon token as well. A semicolon is already allowed after these
tokens, so it's currently a little too restrictive to not have a semicolon
allowed. For example:

    extern {
        fn foo() -> i32; // semicolon after type
    }

    fn main() {
        struct Foo;

        Foo; // semicolon after path
    }