Small spell correction.

src/include/microhttpd.h

@@ -1414,7 +1414,7 @@ enum MHD_OPTION
 
   /**
    * Memory pointer for the certificate (ca.pem) to be used by the
-   * HTTPS daemon for client authentification.
+   * HTTPS daemon for client authentication.
    * This option should be followed by a `const char *` argument.
    */
   MHD_OPTION_HTTPS_MEM_TRUST = 20,

src/include/microhttpd2.h

@@ -2217,7 +2217,7 @@ MHD_daemon_set_tls_psk_callback (struct MHD_Daemon *daemon,
 
 /**
  * Memory pointer for the certificate (ca.pem) to be used by the
- * HTTPS daemon for client authentification.
+ * HTTPS daemon for client authentication.
  *
  * @param daemon daemon to configure tls for
  * @param mem_trust memory pointer to the certificate