FullscreenUI: Use expand icon for dropdowns

dep/imgui/include/IconsPromptFont.h

@@ -374,6 +374,10 @@
 #define ICON_PF_KEY_NUMPAD_EQUAL "\xF0\x9F\xB3\xB8"
 #define ICON_PF_MENU "\xF0\x9F\xB3\xBB"
 #define ICON_PF_KEY_MINUS "\xF0\x9F\xB3\xBC"
+#define ICON_PF_EXPAND_UP_DOWN_FILL "\xF0\x9F\xB1\xA6"
+#define ICON_PF_EXPAND_LEFT_RIGHT_FILL "\xF0\x9F\xB1\xA7"
+#define ICON_PF_EXPAND_UP_DOWN_LINE "\xF0\x9F\xB1\xA8"
+#define ICON_PF_EXPAND_LEFT_RIGHT_LINE "\xF0\x9F\xB1\xA9"
 
 // Platform specific keys.
 #if defined(_WIN32)

src/core/fullscreenui_widgets.cpp

@@ -3995,7 +3995,7 @@ bool FullscreenUI::MenuActionButton(std::string_view title, std::string_view sum
                                     bool dropdown_icon /* = false */, bool enabled /* = true */)
 {
   const SmallString display_value =
-    SmallString::from_format("{}  {}", value, dropdown_icon ? ICON_FA_CHEVRON_DOWN : ICON_FA_CHEVRON_RIGHT);
+    SmallString::from_format("{}  {}", value, dropdown_icon ? ICON_PF_EXPAND_UP_DOWN_LINE : ICON_FA_CHEVRON_RIGHT);
   const float box_padding_x = LayoutScale(15.0f);
   const MenuButtonBounds bb(title, display_value, box_padding_x, summary);