implement suggestions for unknown command/option

src/commonMain/kotlin/com/infendro/cli/util/Distance.kt

@@ -0,0 +1,48 @@
+package com.infendro.cli.util
+
+internal const val threshold = 2
+
+/**
+ * Damerau-Levenshtein string distance
+ */
+internal fun distance(a: String, b: String): Int {
+    if (a == b) return 0
+
+    val n = a.length
+    val m = b.length
+
+    if (n == 0) return m
+    if (m == 0) return n
+
+    var prev2 = IntArray(m + 1)
+    var prev1 = IntArray(m + 1) { it }
+    var curr = IntArray(m + 1)
+
+    for (i in 1..n) {
+        curr[0] = i
+        for (j in 1..m) {
+            val cost = if (a[i - 1] == b[j - 1]) 0 else 1
+
+            curr[j] = minOf(
+                prev1[j] + 1,        // deletion
+                curr[j - 1] + 1,     // insertion
+                prev1[j - 1] + cost, // substitution
+            )
+
+            // transposition
+            if (i > 1 && j > 1 && a[i - 1] == b[j - 2] && a[i - 2] == b[j - 1]) {
+                curr[j] = minOf(
+                    curr[j],
+                    prev2[j - 2] + 1,
+                )
+            }
+        }
+
+        val tmp = prev2
+        prev2 = prev1
+        prev1 = curr
+        curr = tmp
+    }
+
+    return prev1[m]
+}