1394: Fix hover for pat that shadows items r=matklad a=sinkuu
```rust
fn x() {}
fn y() {
let x = 0i32;
x; // hover on `x` is expected to be `i32`, but the actual result was `fn x()`
}
```
This was because: if [`res.is_empty()`](656a0fa9f9/crates/ra_ide_api/src/hover.rs (L205)), it fallbacks to "index based approach" and adds `fn x()` to `res`, which makes [`res.extend(type_of)` below](656a0fa9f9/crates/ra_ide_api/src/hover.rs (L260-L266)) not happen.
Co-authored-by: Shotaro Yamada <sinkuu@sinkuu.xyz>
98020ef2f3