Clippy-fix explicit auto-deref

Seems like these can be safely fixed. With one, I was particularly
surprised -- `Some(pats) => &**pats,` in body.rs?

```
cargo clippy --fix -- -A clippy::all -D clippy::explicit_auto_deref
```

crates/base-db/src/lib.rs

@@ -77,7 +77,7 @@ pub trait SourceDatabase: FileLoader + std::fmt::Debug {
 fn parse_query(db: &dyn SourceDatabase, file_id: FileId) -> Parse<ast::SourceFile> {
     let _p = profile::span("parse_query").detail(|| format!("{:?}", file_id));
     let text = db.file_text(file_id);
-    SourceFile::parse(&*text)
+    SourceFile::parse(&text)
 }
 
 /// We don't want to give HIR knowledge of source roots, hence we extract these