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/resource/materials/materials.json

@@ -235,7 +235,7 @@
         "title": "Variant",
         "description": "UNDOCUMENTED.",
         "$comment": "UNDOCUMENTED",
-        "propertyNames": { "enum": ["fading", "fog", "fog.underwater", "lit", "skinning", "skinning_color", "underlava", "underwater"] },
+        "propertyNames": { "enum": ["fading", "fog", "fog.underwater", "lit", "skinning", "skinning_color", "skinning_alphatest", "underlava", "underwater"] },
         "additionalProperties": {
           "title": "Variant Item",
           "description": "UNDOCUMENTED.",