Fixing piles of clippy errors.

Most of these are calling clone when the struct supports Copy.

Many are using & and &mut on `self` when the function they are called
from already has an immutable or mutable borrow so this isn't needed.

I tried to stay away from actual changes or places where I'd have to
name fresh variables.

milli/src/update/index_documents/extract/extract_geo_points.rs

@@ -60,5 +60,5 @@ pub fn extract_geo_points<R: io::Read + io::Seek>(
         }
     }
 
-    Ok(writer_into_reader(writer)?)
+    writer_into_reader(writer)
 }