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_transform/src/coverage/spans.rs

@@ -6,11 +6,10 @@ use rustc_middle::mir;
 use rustc_span::Span;
 
 use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph};
-use crate::coverage::mappings;
 use crate::coverage::spans::from_mir::{
     extract_covspans_from_mir, ExtractedCovspans, Hole, SpanFromMir,
 };
-use crate::coverage::ExtractedHirInfo;
+use crate::coverage::{mappings, ExtractedHirInfo};
 
 mod from_mir;