Show exception message in bold and underline when logging to TTY
We're already branching error logging format for TTY and non-TTY.
This patch adds bold and underline ANSI color sequence to an error log for TTY.
#1 [ruby-core:83971] Updated by sorah (Sorah Fukumori) about 2 months ago
Note: I proposed this at today's meeting https://bugs.ruby-lang.org/projects/ruby/wiki/DevelopersMeeting20171129Japan