revert renaming of the Density enum and add a FIXME comment instead

Author: scampi

src/config/mod.rs

@@ -92,7 +92,7 @@ create_config! {
         the same line with the pattern of arms";
     force_multiline_blocks: bool, false, false,
         "Force multiline closure bodies and match arms to be wrapped in a block";
-    fn_args_layout: ItemsLayout, ItemsLayout::Tall, true,
+    fn_args_layout: Density, Density::Tall, true,
         "Control the layout of arguments in a function";
     brace_style: BraceStyle, BraceStyle::SameLineWhere, false, "Brace style for items";
     control_brace_style: ControlBraceStyle, ControlBraceStyle::AlwaysSameLine, false,

src/config/options.rs

@@ -58,7 +58,8 @@ pub enum IndentStyle {
 
 #[config_type]
 /// How to place a list-like items.
-pub enum ItemsLayout {
+/// FIXME: Issue-3581: this should be renamed to ItemsLayout when publishing 2.0
+pub enum Density {
     /// Fit as much on one line as possible.
     Compressed,
     /// Items are placed horizontally if sufficient space, vertically otherwise.
@@ -87,13 +88,13 @@ pub enum Heuristics {
     Default,
 }
 
-impl ItemsLayout {
+impl Density {
     pub fn to_list_tactic(self, len: usize) -> ListTactic {
         match self {
-            ItemsLayout::Compressed => ListTactic::Mixed,
-            ItemsLayout::Tall => ListTactic::HorizontalVertical,
-            ItemsLayout::Vertical if len == 1 => ListTactic::Horizontal,
-            ItemsLayout::Vertical => ListTactic::Vertical,
+            Density::Compressed => ListTactic::Mixed,
+            Density::Tall => ListTactic::HorizontalVertical,
+            Density::Vertical if len == 1 => ListTactic::Horizontal,
+            Density::Vertical => ListTactic::Vertical,
         }
     }
 }