Use the same shape to rewrite import when reordering them or not

[ytmimi]

Fixes #4794

The code paths for formatting imports diverge based on the value of
reorder_imports. Each code path used a slightly different shape when
rewriting the imports which lead to issues when reorder_imports = false
and imports_indent = Visual.

Now the code path that rewrites imports without reordering uses the same
shape as the path that also reorders imports.

[ytmimi]

This is the same shape that gets passed to rewrite_top_level from rewrite_reorderable_or_regroupable_items when reorder_imports=true

rustfmt/src/reorder.rs

Lines 131 to 146 in 2d9bc46

	// 4 = "use ", 1 = ";"
	let nested_shape = shape.offset_left(4)?.sub_width(1)?;
	let item_vec: Vec<_> = regrouped_items
	.into_iter()
	.filter(|use_group| !use_group.is_empty())
	.map(|use_group| {
	let item_vec: Vec<_> = use_group
	.into_iter()
	.map(|use_tree| ListItem {
	item: use_tree.rewrite_top_level(context, nested_shape),
	..use_tree.list_item.unwrap_or_else(ListItem::empty)
	})
	.collect();
	wrap_reorderable_items(context, &item_vec, nested_shape)
	})
	.collect::<Option<Vec<_>>>()?;

Now we're using this shape when we call rewrite_top_level from format_import.

[calebcartwright]

I think this is good, but could you add some test cases that have imports nested a few levels (e.g. imports within some in-line mod or other item)

[ytmimi]

could you add some test cases that have imports nested a few levels (e.g. imports within some in-line mod or other item)

@calebcartwright I added the test cases you were looking for. CI is still running right now, but assuming it passes I think we're good to go here!