add data docs

src/commonMain/kotlin/com/insanusmokrassar/krontab/utils/Data.kt

@@ -1,4 +1,12 @@
 package com.insanusmokrassar.krontab.utils
 
+/**
+ * @return [min] in case if [this] less than [min]. Otherwise will check that [max] grant than [this] and return [this]
+ * if so or [max] otherwise
+ */
 internal fun Int.clamp(min: Int, max: Int): Int = if (this < min) min else if (this > max) max else this
+
+/**
+ * Wrapper function for [clamp] extension
+ */
 internal fun Int.clamp(range: IntRange): Int = clamp(range.first, range.last)