Add KDocs

Author: lauzadis

aws-crt-kotlin/native/src/aws/sdk/kotlin/crt/WithCrt.kt

@@ -4,6 +4,9 @@
  */
 package aws.sdk.kotlin.crt
 
+/**
+ * A mixin class used to ensure CRT is initialized before the class is invoked
+ */
 public open class WithCrt() {
     init {
         CRT.initRuntime {  }