color: add some documentation for custom terminfo codes

color: add some documentation for custom terminfo codes

--- a/hgext/color.py	Thu Oct 13 13:10:01 2016 -0700
+++ b/hgext/color.py	Sat Oct 15 15:01:14 2016 -0700
@@ -29,6 +29,15 @@
 Some may not be available for a given terminal type, and will be
 silently ignored.
 
+If the terminfo entry for your terminal is missing codes for an effect
+or has the wrong codes, you can add or override those codes in your
+configuration::
+
+  [color]
+  terminfo.dim = \E[2m
+
+where '\E' is substituted with an escape character.
+
 Labels
 ------