revert to vanilla assets

public/assets/minecraft/shaders/core/gui.fsh

@@ -0,0 +1,22 @@
+#version 330
+
+// Can't moj_import in things used during startup, when resource packs don't exist.
+// This is a copy of dynamicimports.glsl
+layout(std140) uniform DynamicTransforms {
+    mat4 ModelViewMat;
+    vec4 ColorModulator;
+    vec3 ModelOffset;
+    mat4 TextureMat;
+};
+
+in vec4 vertexColor;
+
+out vec4 fragColor;
+
+void main() {
+    vec4 color = vertexColor;
+    if (color.a == 0.0) {
+        discard;
+    }
+    fragColor = color * ColorModulator;
+}