hex: fix comment describing library

Author: pennam

src/hex/hex.h

@@ -14,7 +14,8 @@
 
 namespace arduino { namespace hex {
     /*
-     * This library contains the methods to get board provisioning id
+     * This library contains the methods to hex encode a buffer into a String
+     * and viceversa
      */
 
     String encode(const uint8_t* in, uint32_t size);