LIBRETRO: Add sc8, xo8 and hc8 to the list of valid extensions

I wasn't aware of these extensions. Add them

jaxe_libretro.info

 display_name = "CHIP-8/SuperChip8/XO-CHIP"
 authors = "Kurtis Dinelle"
-supported_extensions = "ch8"
+supported_extensions = "ch8|sc8|xo8|hc8"
 corename = "JAXE"
 manufacturer = "RCA"
 categories = "Emulator"

src/libretro.c

@@ -419,7 +419,7 @@ void retro_get_system_info(struct retro_system_info *info)
 #define GIT_VERSION ""
 #endif
     info->library_version = "1.0" GIT_VERSION;
-    info->valid_extensions = "ch8";
+    info->valid_extensions = "ch8|sc8|xo8|hc8";
     info->need_fullpath = false;
 }