7520: Show alias underlying type r=lnicola a=lumenian

Closes #7511 

Display underlying type in the tooltip:
```rust
pub type SomeAlias = f64
```
instead of:
```rust
pub type SomeAlias
```

Co-authored-by: lumenian <lumenian@gmail.com>
This commit is contained in:
bors[bot] 2021-02-02 14:59:29 +00:00 committed by GitHub
commit cc3112de1b
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@ -61,7 +61,11 @@ impl ShortLabel for ast::BlockExpr {
impl ShortLabel for ast::TypeAlias {
fn short_label(&self) -> Option<String> {
short_label_from_node(self, "type ")
let mut buf = short_label_from_node(self, "type ")?;
if let Some(type_ref) = self.ty() {
format_to!(buf, " = {}", type_ref.syntax());
}
Some(buf)
}
}