doc: document explicitly that you can use prefixes for setchannelfee 'base'

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

doc/lightning-setchannelfee.7

@@ -1,13 +1,13 @@
 '\" t
 .\"     Title: lightning-setchannelfee
 .\"    Author: [see the "AUTHOR" section]
-.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
-.\"      Date: 03/12/2019
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\"      Date: 03/15/2019
 .\"    Manual: \ \&
 .\"    Source: \ \&
 .\"  Language: English
 .\"
-.TH "LIGHTNING\-SETCHANNE" "7" "03/12/2019" "\ \&" "\ \&"
+.TH "LIGHTNING\-SETCHANNE" "7" "03/15/2019" "\ \&" "\ \&"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -38,7 +38,7 @@ The \fBsetchannelfee\fR RPC command sets channel specific routing fees as define
 .sp
 \fIid\fR is required and should contain a scid (short channel ID), channel id or peerid (pubkey) of the channel to be modified\&.
 .sp
-\fIbase\fR is an optional value in millisatoshi that is added as base fee to any routed payment\&. If the parameter is left out, the global config value fee\-base will be used again\&.
+\fIbase\fR is an optional value in millisatoshi that is added as base fee to any routed payment\&. If the parameter is left out, the global config value fee\-base will be used again\&. It can be a whole number, or a whole number ending in \fImsat\fR or \fIsat\fR, or a number with three decimal places ending in \fIsat\fR, or a number with 1 to 11 decimal places ending in \fIbtc\fR\&.
 .sp
 \fIppm\fR is an optional value that is added proportionally per\-millionths to any routed payment volume in satoshi\&. For example, if ppm is 1,000 and 1,000,000 satoshi is being routed trhough the channel, an proportional fee of 1,000 satoshi is added, resulting in a 0\&.1% fee\&. If the parameter is left out, the global config value will be used again\&.
 .SH "RETURN VALUE"

doc/lightning-setchannelfee.7.txt

@@ -22,7 +22,9 @@ or peerid (pubkey) of the channel to be modified.
 
 'base' is an optional value in millisatoshi that is added as base fee to
 any routed payment. If the parameter is left out, the global config
-value fee-base will be used again.
+value fee-base will be used again. It can be a whole number, or a whole number ending in 'msat' or
+'sat', or a number with three decimal places ending in 'sat', or a number
+with 1 to 11 decimal places ending in 'btc'.
 
 'ppm' is an optional value that is added proportionally per-millionths to
 any routed payment volume in satoshi. For example, if ppm is 1,000 and