docs: update wording on autopilot.allocation

Fixes #681.

sample-lnd.conf

@@ -248,6 +248,8 @@ litecoin.node=btcd
 ; The maximum number of channels that should be created.
 ; autopilot.maxchannels=5
 
-; The percentage of total funds that should be committed to automatic channel
-; establishment
+; The fraction of total funds that should be committed to automatic channel
+; establishment. For example 0.6 means that 60% of the total funds available
+; within the wallet should be used to automatically establish channels. The total
+; amount of attempted channels will still respect the maxchannels param.
 ; autopilot.allocation=0.6