Make 'current-fg' inherit from 'fg' to simplify configuration

If you do not want 'current-fg' to inherit attributes of 'fg', prefix it
with 'regular:' to reset them.

  # italic and underline
  fzf --color fg:italic,current-fg:underline

  # only underline
  fzf --color fg:italic,current-fg:regular:underline

src/ansi.go

@@ -44,7 +44,7 @@ func (s *ansiState) ToString() string {
 	}
 
 	ret := ""
-	if s.attr&tui.Bold > 0 {
+	if s.attr&tui.Bold > 0 || s.attr&tui.BoldForce > 0 {
 		ret += "1;"
 	}
 	if s.attr&tui.Dim > 0 {