Add docs to writeByteArray

src/main/kotlin/ru/dbotthepony/kommons/io/OutputStreamUtils.kt

@@ -311,11 +311,17 @@ fun <S : OutputStream, V : Any> S.writeOptional(value: Optional<V>, writer: S.(V
 	}
 }
 
+/**
+ * Writes array's size as variable length integer and then writes its contents
+ */
 fun OutputStream.writeByteArray(value: ByteArray) {
 	writeVarInt(value.size)
 	write(value)
 }
 
+/**
+ * Writes array's size as variable length integer and then writes its contents
+ */
 fun OutputStream.writeByteArray(value: ByteArray, offset: Int, length: Int) {
 	Objects.checkFromIndexSize(offset, value.size, length)
 	writeVarInt(length)