Description of problem:
Bold debug info of nbdkit command is difficult to read when the background of the terminal box is black

Version-Release number of selected component (if applicable):
nbdkit-1.34.1-1.el9.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Check debug information of nbdkit command when the background of the terminal box is black, found bond messages is difficult to read, please refer to the screenshot 'bold-debug-info-of-nbdkit.png'

1. nbdkit -vr curl url='https://10.73.212.129/folder/esx8.0-rhel9.3-x86_64_1/esx8.0-rhel9.3-x86_64-flat.vmdk?dcPath=data&dsName=esx8.0-matrix' password=+/home/passwd user=root sslverify=false --run 'nbdinfo $uri'
   ....
   protocol: newstyle-fixed without TLS, using structured packets
   export="":
   export-size: 12884901888 (12G)
   content: DOS/MBR boot sector
   uri: nbd://localhost:10809/
   contexts:
   base:allocation
   is_rotational: false
   is_read_only: true
   can_cache: false
   can_df: true
   can_fast_zero: false
   can_flush: false
   can_fua: false
   can_multi_conn: true
   can_trim: false
   can_zero: false

Actual results
As above description

Expected results:
Bold debug information of nbdkit command is clear when the background of the terminal box is black

As above description

Additional info: