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

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

src/fontcache/freetypefontcache.cpp

@@ -241,7 +241,7 @@ const Sprite *FreeTypeFontCache::InternalGetGlyph(GlyphID key, bool aa)
 	/* FreeType has rendered the glyph, now we allocate a sprite and copy the image into it */
 	SpriteLoader::Sprite sprite;
 	sprite.AllocateData(ZOOM_LVL_NORMAL, static_cast<size_t>(width) * height);
-	sprite.type = ST_FONT;
+	sprite.type = SpriteType::Font;
 	sprite.colours = (aa ? SCC_PAL | SCC_ALPHA : SCC_PAL);
 	sprite.width = width;
 	sprite.height = height;

src/fontcache/spritefontcache.cpp

@@ -113,14 +113,14 @@ const Sprite *SpriteFontCache::GetGlyph(GlyphID key)
 {
 	SpriteID sprite = this->GetUnicodeGlyph(key);
 	if (sprite == 0) sprite = this->GetUnicodeGlyph('?');
-	return GetSprite(sprite, ST_FONT);
+	return GetSprite(sprite, SpriteType::Font);
 }
 
 uint SpriteFontCache::GetGlyphWidth(GlyphID key)
 {
 	SpriteID sprite = this->GetUnicodeGlyph(key);
 	if (sprite == 0) sprite = this->GetUnicodeGlyph('?');
-	return SpriteExists(sprite) ? GetSprite(sprite, ST_FONT)->width + ScaleSpriteTrad(this->fs != FS_NORMAL ? 1 : 0) : 0;
+	return SpriteExists(sprite) ? GetSprite(sprite, SpriteType::Font)->width + ScaleSpriteTrad(this->fs != FS_NORMAL ? 1 : 0) : 0;
 }
 
 bool SpriteFontCache::GetDrawGlyphShadow()

src/fontcache/truetypefontcache.cpp

@@ -141,7 +141,7 @@ const Sprite *TrueTypeFontCache::GetGlyph(GlyphID key)
 				8,  // width
 				0,  // x_offs
 				0,  // y_offs
-				ST_FONT,
+				SpriteType::Font,
 				SCC_PAL,
 				builtin_questionmark_data
 			};