Add bold, italic and monospace font styling for HUD text elements (#11478)

Co-authored-by: Elias Fleckenstein <eliasfleckenstein@web.de>

src/hud.cpp

@@ -50,6 +50,7 @@ const struct EnumString es_HudElementStat[] =
 	{HUD_STAT_SIZE,    "size"},
 	{HUD_STAT_Z_INDEX, "z_index"},
 	{HUD_STAT_TEXT2,   "text2"},
+	{HUD_STAT_STYLE,   "style"},
 	{0, NULL},
 };