Codechange: Make SpriteType, CargoSortType, SourceType and ScriptType enum classes. (#10663)

This avoids a (soft) namespace conflict between the four ST_* enums.

src/os/macosx/font_osx.cpp

@@ -287,7 +287,7 @@ const Sprite *CoreTextFontCache::InternalGetGlyph(GlyphID key, bool use_aa)
 
 	SpriteLoader::Sprite sprite;
 	sprite.AllocateData(ZOOM_LVL_NORMAL, width * height);
-	sprite.type = ST_FONT;
+	sprite.type = SpriteType::Font;
 	sprite.colours = (use_aa ? SCC_PAL | SCC_ALPHA : SCC_PAL);
 	sprite.width = width;
 	sprite.height = height;