s/OptionMenu/OptionsMenu

As per the PSX debug info:

	struct OMENUITEM MemcardLoadOptionsMenu[4]
	struct OMENUITEM MemcardSaveOptionsMenu[4]

Source/gamemenu.cpp

@@ -21,7 +21,7 @@ TMenuItem MultiMenu[5] = {
 	{ GMENU_ENABLED, NULL,              NULL                   }
 	// clang-format on
 };
-TMenuItem OptionMenu[6] = {
+TMenuItem OptionsMenu[6] = {
 	// clang-format off
 	//                     dwFlags, pszStr,          fnMenu
 	{ GMENU_ENABLED | GMENU_SLIDER, NULL,            &gamemenu_music_volume  },
@@ -166,12 +166,12 @@ void gamemenu_options(BOOL bActivate)
 	gamemenu_get_sound();
 	gamemenu_get_gamma();
 	gamemenu_get_color_cycling();
-	gmenu_call_proc(OptionMenu, NULL);
+	gmenu_call_proc(OptionsMenu, NULL);
 }
 
 void gamemenu_get_music()
 {
-	gamemenu_sound_music_toggle(music_toggle_names, OptionMenu, sound_get_or_set_music_volume(1));
+	gamemenu_sound_music_toggle(music_toggle_names, OptionsMenu, sound_get_or_set_music_volume(1));
 }
 
 void gamemenu_sound_music_toggle(char **names, TMenuItem *menu_item, int volume)
@@ -190,18 +190,18 @@ void gamemenu_sound_music_toggle(char **names, TMenuItem *menu_item, int volume)
 
 void gamemenu_get_sound()
 {
-	gamemenu_sound_music_toggle(sound_toggle_names, &OptionMenu[1], sound_get_or_set_sound_volume(1));
+	gamemenu_sound_music_toggle(sound_toggle_names, &OptionsMenu[1], sound_get_or_set_sound_volume(1));
 }
 
 void gamemenu_get_color_cycling()
 {
-	OptionMenu[3].pszStr = color_cycling_toggle_names[palette_get_colour_cycling() & 1];
+	OptionsMenu[3].pszStr = color_cycling_toggle_names[palette_get_colour_cycling() & 1];
 }
 
 void gamemenu_get_gamma()
 {
-	gmenu_slider_steps(&OptionMenu[2], 15);
-	gmenu_slider_set(&OptionMenu[2], 30, 100, UpdateGamma(0));
+	gmenu_slider_steps(&OptionsMenu[2], 15);
+	gmenu_slider_set(&OptionsMenu[2], 30, 100, UpdateGamma(0));
 }
 
 void gamemenu_music_volume(BOOL bActivate)
@@ -222,7 +222,7 @@ void gamemenu_music_volume(BOOL bActivate)
 		return;
 	}
 
-	volume = gamemenu_slider_music_sound(OptionMenu);
+	volume = gamemenu_slider_music_sound(OptionsMenu);
 	sound_get_or_set_music_volume(volume);
 
 	if (volume == VOLUME_MIN) {
@@ -264,7 +264,7 @@ void gamemenu_sound_volume(BOOL bActivate)
 			sound_get_or_set_sound_volume(VOLUME_MAX);
 		}
 	} else {
-		volume = gamemenu_slider_music_sound(&OptionMenu[1]);
+		volume = gamemenu_slider_music_sound(&OptionsMenu[1]);
 		sound_get_or_set_sound_volume(volume);
 		if (volume == VOLUME_MIN) {
 			if (gbSoundOn) {
@@ -297,7 +297,7 @@ void gamemenu_gamma(BOOL bActivate)
 
 int gamemenu_slider_gamma()
 {
-	return gmenu_slider_get(&OptionMenu[2], 30, 100);
+	return gmenu_slider_get(&OptionsMenu[2], 30, 100);
 }
 
 void gamemenu_color_cycling(BOOL bActivate)
@@ -305,5 +305,5 @@ void gamemenu_color_cycling(BOOL bActivate)
 	BOOL color_cycling;
 
 	color_cycling = palette_set_color_cycling(palette_get_colour_cycling() == 0);
-	OptionMenu[3].pszStr = color_cycling_toggle_names[color_cycling & 1];
+	OptionsMenu[3].pszStr = color_cycling_toggle_names[color_cycling & 1];
 }