Add YGGutter Enum

Summary:
This adds the YGGutter enum, used to choose between row/column gap variants (row-gap, column-gap, gap).

This used later in changes from https://github.com/facebook/yoga/pull/1116, in the APIs which deal with setting gap on style on yoga node.

Note the original PR called this `YGGap`, but this ending up leading to a couple public method signatures that could appear ambiguous:
1. `SetGap(YGGap gap, float gapLength)`: Enums like `YGAlign` are the vaues for an `align` prop. `YGGap` controls the variant of the gap (like `YGEdge` does for left/right/top/bottom variants). So the enum reads as if it is the `gapValue`, and it looks like we have two of the same parameter.
2. `SetGap(YGGap gapDirection, float gap)`: This is misleading, because the direction gaps flow is the cross-axis of flex-direction.
3. `GetGap(YGGap gap)`: `gap` is the variant, but looks like an out param.

The [CSS Box Alignment](https://www.w3.org/TR/css-align-3/#column-row-gap) spec refers to these gaps as "Gutters", which removes the ambiguity.

Changelog:
[General][Added] - Add YGGutter Enum

Reviewed By: yungsters

Differential Revision: D39922412

fbshipit-source-id: 4b0baf800fecb3d03560a4267c7fb4c4330fd39e

java/com/facebook/yoga/YogaGutter.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// @generated by enums.py
+
+package com.facebook.yoga;
+
+public enum YogaGutter {
+  COLUMN(0),
+  ROW(1),
+  ALL(2);
+
+  private final int mIntValue;
+
+  YogaGutter(int intValue) {
+    mIntValue = intValue;
+  }
+
+  public int intValue() {
+    return mIntValue;
+  }
+
+  public static YogaGutter fromInt(int value) {
+    switch (value) {
+      case 0: return COLUMN;
+      case 1: return ROW;
+      case 2: return ALL;
+      default: throw new IllegalArgumentException("Unknown enum value: " + value);
+    }
+  }
+}