editor: Qualify RangeExt::overlaps call to prevent phantom diagnostics (#18743)

This PR qualifies a call to `RangeExt::overlaps` to avoid some confusion
in rust-analyzer not being able to distinguish between
`RangeExt::overlaps` and `AnchorRangeExt::overlaps` and producing
phantom diagnostics.

We may also want to consider renaming the method on `AnchorRangeExt` to
disambiguate them.

Release Notes:

- N/A

crates/editor/src/editor.rs

@@ -10792,7 +10792,7 @@ impl Editor {
             .selections
             .all::<Point>(cx)
             .iter()
-            .any(|selection| selection.range().overlaps(&intersection_range));
+            .any(|selection| RangeExt::overlaps(&selection.range(), &intersection_range));
 
         self.unfold_ranges(std::iter::once(intersection_range), true, autoscroll, cx)
     }