Do not assume that each character takes at least 1 column

Fixes #2163, though this is not a proper fix to the problem.

src/tui/light.go

@@ -831,7 +831,7 @@ func wrapLine(input string, prefixLength int, max int, tabstop int) []wrappedLin
 	width := 0
 	line := ""
 	for _, r := range input {
-		w := util.Max(util.RuneWidth(r, prefixLength+width, 8), 1)
+		w := util.RuneWidth(r, prefixLength+width, 8)
 		width += w
 		str := string(r)
 		if r == '\t' {