patch 8.2.3562: cannot add color names

Problem:    Cannot add color names.
Solution:   Add the v:colornames dictionary. (Drew Vogel, closes #8761)
diff --git a/runtime/doc/os_haiku.txt b/runtime/doc/os_haiku.txt
index 5c520b0..a22b99b 100644
--- a/runtime/doc/os_haiku.txt
+++ b/runtime/doc/os_haiku.txt
@@ -194,9 +194,8 @@
 
 11. Color names						*haiku-colors*
 
-Vim has a number of color names built-in.  Additional names are read from the
-file $VIMRUNTIME/rgb.txt, if present.  This file is basically the color
-database from X.  Names used from this file are cached for efficiency.
+Vim has a number of color names built-in. Additional names can be defined in
+|v:colornames|. See |:colorscheme| for details.
 
 
 12. GUI Toolbar Images					*haiku-toolbar-images*