add a comment on the :light_black entry

Author: tkelman

base/client.jl

@@ -12,7 +12,7 @@ const text_colors = AnyDict(
     :magenta       => "\033[35m",
     :cyan          => "\033[36m",
     :white         => "\033[37m",
-    :light_black   => "\033[90m",
+    :light_black   => "\033[90m", # gray
     :light_red     => "\033[91m",
     :light_green   => "\033[92m",
     :light_yellow  => "\033[93m",