Tweak the documentation for BridgeDistribution

Note that it will have no effect yet; note that the default is
"any".

changes/feature18329

@@ -2,5 +2,8 @@
     - Bridge relays can now set the BridgeDistribution config option to
       add a "bridge-distribution-request" line to their bridge descriptor,
       which tells BridgeDB how they'd like their bridge address to be
-      given out. Implements tickets 18329.
+      given out. (Note that as of Oct 2017, BridgeDB does not yet implement
+      this feature.) As a side benefit, this feature provides a way
+      to distinguish bridge descriptors from non-bridge descriptors.
+      Implements tickets 18329.
 

doc/tor.1.txt

@@ -1651,7 +1651,12 @@ is non-zero):
     If set along with BridgeRelay, Tor will include a new line in its
     bridge descriptor which indicates to the BridgeDB service how it
     would like its bridge address to be given out. Set it to "none" if
-    you want BridgeDB to avoid distributing your bridge address.
+    you want BridgeDB to avoid distributing your bridge address, or "any" to
+    let BridgeDB decide. (Default: any)
+ +
+    Note: as of Oct 2017, the BridgeDB part of this option is not yet
+    implemented.  Until BridgeDB is updated to obey this option, your
+    bridge will make this request, but it will not (yet) be obeyed.
 
 [[ContactInfo]] **ContactInfo** __email_address__::
     Administrative contact information for this relay or bridge. This line