fix: add healing metric type for heal tracing (#15631)

changes the `heal.checkBucket` to `heal.Bucket` instead
since the latter is more meaningful.

cmd/healingmetric_string.go

@@ -0,0 +1,24 @@
+// Code generated by "stringer -type=healingMetric -trimprefix=healingMetric erasure-healing.go"; DO NOT EDIT.
+
+package cmd
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[healingMetricBucket-0]
+	_ = x[healingMetricObject-1]
+}
+
+const _healingMetric_name = "BucketObject"
+
+var _healingMetric_index = [...]uint8{0, 6, 12}
+
+func (i healingMetric) String() string {
+	if i >= healingMetric(len(_healingMetric_index)-1) {
+		return "healingMetric(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _healingMetric_name[_healingMetric_index[i]:_healingMetric_index[i+1]]
+}