Updated quick pick and suggest widget colors (#199)

VS Code 1.57 [1] (May 2021) introduced new color tokens for the
"quick pick" and "editor suggest" widgets [2] in focused state to better
align with the tree widget styles.
These changes broke the current style of Nord and made the theme har to
use. The new keys have now been added to make it conform with Nord's
style:

- `editorSuggestWidget.focusHighlightForeground` - color of the match
  highlights in the suggest widget when an item is focused.
- `editorSuggestWidget.selectedForeground` - foreground color of the
  selected entry in the suggest widget.
- `list.focusHighlightForeground` - list/tree foreground color of the
  match highlights on actively focused items when searching inside the
  list/tree.
- `quickInputList.focusForeground` - quick picker foreground color for
  the focused item.

[1]: https://code.visualstudio.com/updates/v1_57
[2]: https://code.visualstudio.com/updates/v1_57#_updated-quick-pick-suggest-widget-colors

Co-authored-by: Sven Greb <development@svengreb.de>

Closes GH-196

themes/nord-color-theme.json

@@ -98,8 +98,10 @@
     "editorSuggestWidget.background": "#2e3440",
     "editorSuggestWidget.border": "#3b4252",
     "editorSuggestWidget.foreground": "#d8dee9",
+    "editorSuggestWidget.focusHighlightForeground": "#88c0d0",
     "editorSuggestWidget.highlightForeground": "#88c0d0",
     "editorSuggestWidget.selectedBackground": "#434c5e",
+    "editorSuggestWidget.selectedForeground": "#d8dee9",
     "extensionButton.prominentForeground": "#d8dee9",
     "extensionButton.prominentBackground": "#434c5e",
     "extensionButton.prominentHoverBackground": "#4c566a",
@@ -130,6 +132,7 @@
     "list.hoverForeground": "#eceff4",
     "list.focusForeground": "#d8dee9",
     "list.focusBackground": "#88c0d099",
+    "list.focusHighlightForeground": "#eceff4",
     "list.hoverBackground": "#3b4252",
     "list.dropBackground": "#88c0d099",
     "list.highlightForeground": "#88c0d0",
@@ -195,6 +198,7 @@
     "pickerGroup.border": "#3b4252",
     "pickerGroup.foreground": "#88c0d0",
     "progressBar.background": "#88c0d0",
+    "quickInputList.focusForeground": "#2e3440",
     "scrollbar.shadow": "#00000066",
     "scrollbarSlider.activeBackground": "#434c5eaa",
     "scrollbarSlider.background": "#434c5e99",