scripts: Prefer 1;30-37m ansi codes over 90-97m

Reading Wikipedia:

> Later terminals added the ability to directly specify the "bright"
> colors with 90–97 and 100–107.

So if we want to stick to one pattern, we should probably go with
brightness as a separate modifier.

This shouldn't noticeably change any script, unless your terminal
interprets 90-97m colors differently from 1;30-37m, in which case things
should be more consistent now.

scripts/dbgbmap.py

@@ -87,7 +87,7 @@ COLORS = {
     'data':     '32',
     'corrupt':  '31',
     'conflict': '30;41',
-    'unused':   '90',
+    'unused':   '1;30',
 }
 
 # give more interesting objects a higher priority