Added very minor code comments

src/TinyGsmClientMC60.h

@@ -662,6 +662,10 @@ public:
     return res;
   }
 
+  /*
+   * Client related functions
+   */
+
 protected:
 
   bool modemConnect(const char* host, uint16_t port, uint8_t mux, bool ssl = false) {