Support attaching format information to selected color variables

doc/config

@@ -328,8 +328,6 @@
 ##
 #progressbar_look = =>
 #
-#progressbar_boldness = yes
-#
 ## Available values: database, playlist.
 ##
 #default_place_to_search_in = database
@@ -496,6 +494,15 @@
 ## the bottom of the help screen for list of available colors
 ## and their numerical values.
 ##
+## Moreover, it is possible to attach format information to
+## selected color variables by appending to their end a
+## colon followed by one or more format flags, e.g. black:b
+## or red:ur. The following variables support this syntax:
+## visualizer_color, color1, color2, empty_tag_color,
+## volume_color, state_line_color, state_flags_color,
+## progressbar_color, progressbar_elapsed_color,
+## alternative_ui_separator_color.
+##
 ## Note: due to technical limitations of ncurses, if 256 colors
 ## are used, it is possible to either use only the colors with
 ## default background color, or all pairs from 1_1 up to 254_127,
@@ -512,7 +519,7 @@
 #
 #state_line_color = default
 #
-#state_flags_color = default
+#state_flags_color = default:b
 #
 #main_window_color = yellow
 #
@@ -522,13 +529,13 @@
 #
 #main_window_highlight_color = yellow
 #
-#progressbar_color = black
+#progressbar_color = black:b
 #
-#progressbar_elapsed_color = green
+#progressbar_elapsed_color = green:b
 #
 #statusbar_color = default
 #
-#alternative_ui_separator_color = black
+#alternative_ui_separator_color = black:b
 #
 #active_column_color = red
 #