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.

library/core/src/tuple.rs

@@ -1,9 +1,7 @@
 // See core/src/primitive_docs.rs for documentation.
 
 use crate::cmp::Ordering::{self, *};
-use crate::marker::ConstParamTy_;
-use crate::marker::StructuralPartialEq;
-use crate::marker::UnsizedConstParamTy;
+use crate::marker::{ConstParamTy_, StructuralPartialEq, UnsizedConstParamTy};
 
 // Recursive macro for implementing n-ary tuple functions and operations
 //