Fix max client name length in HiddenServiceAuthorizeClient description

REND_CLIENTNAME_MAX_LEN is set to 16, not 19.

changes/bug11118

@@ -0,0 +1,3 @@
+  o Documentation:
+    - Fix max client name length in HiddenServiceAuthorizeClient description:
+      should have been 16 and not 19. Fix ticket 11118.

doc/tor.1.txt

@@ -2032,7 +2032,7 @@ The following options are used to configure a hidden service.
     authorization protocol or \'stealth' for a less scalable protocol that also
     hides service activity from unauthorized clients. Only clients that are
     listed here are authorized to access the hidden service. Valid client names
-    are 1 to 19 characters  long and only use characters in A-Za-z0-9+-_ (no
+    are 1 to 16 characters long and only use characters in A-Za-z0-9+-_ (no
     spaces). If this option is set, the hidden service is not accessible for
     clients without authorization any more. Generated authorization data can be
     found in the hostname file. Clients need to put this authorization data in