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/tui/light.go

@@ -1011,7 +1011,7 @@ func attrCodes(attr Attr) []string {
 	if (attr & AttrClear) > 0 {
 		return codes
 	}
-	if (attr & Bold) > 0 {
+	if (attr&Bold) > 0 || (attr&BoldForce) > 0 {
 		codes = append(codes, "1")
 	}
 	if (attr & Dim) > 0 {