Reformat use declarations.

The previous commit updated `rustfmt.toml` appropriately. This commit is
the outcome of running `x fmt --all` with the new formatting options.

compiler/rustc_mir_dataflow/src/points.rs

@@ -1,10 +1,10 @@
-use crate::framework::{visit_results, ResultsVisitable, ResultsVisitor};
 use rustc_index::bit_set::BitSet;
 use rustc_index::interval::SparseIntervalMatrix;
-use rustc_index::Idx;
-use rustc_index::IndexVec;
+use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::{self, BasicBlock, Body, Location};
 
+use crate::framework::{visit_results, ResultsVisitable, ResultsVisitor};
+
 /// Maps between a `Location` and a `PointIndex` (and vice versa).
 pub struct DenseLocationMap {
     /// For each basic block, how many points are contained within?