Fixes to enchantments, loot tables, and materials, and typo fixes. (#372)

-   Added the missing enchantment types to the enum for the `minecraft:enchantable` item component.
-   Fixed a typo where the `killed_by_player_or_pets` condition was called "Killed By Player Or Pets Or Pets" instead of "Killed By Player Or Pets".
-   Fixed the match tool loot table condition to use the correct schema for the `enchantments` property.
-   Fixed a typo where the title of the match tool loot table condition schema was "Killed By Player" instead of "Match Tool".
-   Added the missing `skinning_alphatest` value to the variant enum for materials (this variant type is used in the vanilla material files).
-   Fixed a typo where the title of the `skins.json` schema was "Skip Pack" instead of "Skin Pack".

source/skinpacks/skins.json

@@ -1,6 +1,6 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema",
-  "title": "Skip Pack",
+  "title": "Skin Pack",
   "description": "Skin pack definition.",
   "type": "object",
   "additionalProperties": false,