Update stb_truetype.h

stb_truetype.h

@@ -978,6 +978,7 @@ static int stbtt__isfont(stbtt_uint8 *font)
    if (stbtt_tag(font, "typ1"))   return 1; // TrueType with type 1 font -- we don't support this!
    if (stbtt_tag(font, "OTTO"))   return 1; // OpenType with CFF
    if (stbtt_tag4(font, 0,1,0,0)) return 1; // OpenType 1.0
+   if (stbtt_tag(font, "true"))   return 1; // Apple specification for TrueType fonts
    return 0;
 }