Improve diagnostics for multiple use wildcards

[pickfire]

I tried this code:

use hello::schema::*::dsl::*;

I expected to see this happen: Import from wildcard of wildcard

Instead, this happened: It errors saying expected semicolon, then I realized that multiple * is not supported, but the error message should show that only one wildcard is supported.

 --> src/main.rs:4:25
  |
4 |     use hello::schema::*::dsl::*;
  |                         ^^ expected `;`

And then I tried

use hello::schema::{users, posts, comments}::dsl::*;

But I got another error

error: expected `;`, found `::`
 --> src/main.rs:4:48
  |
4 |     use hello::schema::{users, posts, comments}::dsl::*;
  |                                                ^^ expected `;`

Which I guess using only one wildcard isn't true.

Meta

rustc --version --verbose:

rustc 1.48.0 (7eac88abb 2020-11-16)
binary: rustc
commit-hash: 7eac88abb2e57e752f3302f02be5f3ce3d7adfb4
commit-date: 2020-11-16
host: x86_64-unknown-linux-gnu
release: 1.48.0
LLVM version: 11.0