Parse error in tuple access  `foo.0. bar`

This is supported rust syntax since rust 1.46, but rust-analyzer fail to parse it in some cases:

The following code compiles fine, but rust-analizer incorrectly reports an error:
```rust
fn main() {
    let foo = (String::new(),);
    foo.0.as_str(); // OK
    foo.0. as_str(); // ERROR in rust-analyzer! (Syntax Error: expected SEMICOLON);
}
```
