Incorrect links to the online documentation in popups

[rgeorgiev583]

When I hover over a token which is defined in the standard library, a popup comes up with a link to its definition on the official Rust stdlib reference website. However, this link is always broken because the URL which it points to uses an addressing convention which seems to be obsolete. For instance:

• the URL for std::path::Path is https://doc.rust-lang.org/nightly/std/path/Path.t.html when it should have been https://doc.rust-lang.org/nightly/std/path/struct.Path.html;
• the URL for std::env::args is https://doc.rust-lang.org/nightly/std/env/args.v.html when it should have been https://doc.rust-lang.org/nightly/std/env/fn.args.html.