Updates custom menu borders and item styles (microsoft#164165)

Updates menu item margin and radius and adds border to default themes

Author: daviddossett

extensions/theme-defaults/themes/dark_vs.json

@@ -12,8 +12,10 @@
 		"activityBarBadge.background": "#007ACC",
 		"sideBarTitle.foreground": "#BBBBBB",
 		"input.placeholderForeground": "#A6A6A6",
-		"menu.background": "#303031",
+		"menu.background": "#252526",
 		"menu.foreground": "#CCCCCC",
+		"menu.separatorBackground": "#454545",
+		"menu.border": "#454545",
 		"statusBarItem.remoteForeground": "#FFF",
 		"statusBarItem.remoteBackground": "#16825D",
 		"ports.iconRunningProcessForeground": "#369432",

extensions/theme-defaults/themes/light_vs.json

@@ -13,6 +13,7 @@
 		"activityBarBadge.background": "#007ACC",
 		"sideBarTitle.foreground": "#6F6F6F",
 		"list.hoverBackground": "#E8E8E8",
+		"menu.border": "#D4D4D4",
 		"input.placeholderForeground": "#767676",
 		"searchEditor.textInputBorder": "#CECECE",
 		"settings.textInputBorder": "#CECECE",

src/vs/base/browser/ui/menu/menu.ts

@@ -1128,6 +1128,8 @@ ${formatRule(Codicon.menuSubmenu)}
 	height: 2em;
 	align-items: center;
 	position: relative;
+	margin: 0 4px;
+	border-radius: 4px;
 }
 
 .monaco-menu .monaco-action-bar.vertical .action-menu-item:hover .keybinding,
@@ -1251,7 +1253,7 @@ ${formatRule(Codicon.menuSubmenu)}
 /* Vertical Action Bar Styles */
 
 .monaco-menu .monaco-action-bar.vertical {
-	padding: .6em 0;
+	padding: 4px 0;
 }
 
 .monaco-menu .monaco-action-bar.vertical .action-menu-item {