Add tooltip to minimap toggle control

data/core.yaml

@@ -267,8 +267,10 @@ en:
     custom_button: Edit custom background
     custom_prompt: "Enter a tile URL template. Valid tokens are {z}, {x}, {y} for Z/X/Y scheme and {u} for quadtile scheme."
     fix_misalignment: Fix alignment
-    toggle_minimap: Minimap
     reset: reset
+    minimap:
+      description: Minimap
+      tooltip: Show a zoomed out map to help locate the area currently displayed.
   map_data:
     title: Map Data
     description: Map Data

dist/locales/en.json

@@ -323,8 +323,11 @@
         "custom_button": "Edit custom background",
         "custom_prompt": "Enter a tile URL template. Valid tokens are {z}, {x}, {y} for Z/X/Y scheme and {u} for quadtile scheme.",
         "fix_misalignment": "Fix alignment",
-        "toggle_minimap": "Minimap",
-        "reset": "reset"
+        "reset": "reset",
+        "minimap": {
+            "description": "Minimap",
+            "tooltip": "Show a zoomed out map to help locate the area currently displayed."
+        }
     },
     "map_data": {
         "title": "Map Data",

js/id/ui/background.js

@@ -255,7 +255,13 @@ iD.ui.Background = function(context) {
         var controls = content.append('div')
             .attr('class', 'controls-list');
 
-        var minimapLabel = controls.append('label');
+        var minimapLabel = controls
+            .append('label')
+            .call(bootstrap.tooltip()
+                .html(true)
+                .title(iD.ui.tooltipHtml(t('background.minimap.tooltip'), '/'))
+                .placement('top')
+            );
 
         minimapLabel.classed('minimap-toggle', true)
             .append('input')
@@ -263,10 +269,10 @@ iD.ui.Background = function(context) {
             .on('change', function() {
                 iD.ui.MapInMap.toggle();
                 d3.event.preventDefault();
-            });
+            })
 
         minimapLabel.append('span')
-            .text(t('background.toggle_minimap'));
+            .text(t('background.minimap.description'));
 
         var adjustments = content.append('div')
             .attr('class', 'adjustments');