fix(ansi): reset uniseq grapheme state after

We need to reset the grapheme state after encountering a non-printable
character or when we're not using uniseg for string width (ASCII
printables have a width of 1 cell).

Fixes: #122
Fixes: #123
Fixes: charmbracelet/lipgloss#332

ansi/width.go

@@ -90,6 +90,10 @@ func StringWidth(s string) int {
 				continue
 			}
 			width++
+			fallthrough
+		default:
+			// Reset uniseg state when we're not in a printable state.
+			gstate = -1
 		}
 
 		pstate = state

ansi/width_test.go

@@ -31,6 +31,7 @@ var cases = []struct {
 	{"unicode", "\x1b[35m“box”\x1b[0m", "“box”", 5},
 	{"just_unicode", "Claire’s Boutique", "Claire’s Boutique", 17},
 	{"unclosed_ansi", "Hey, \x1b[7m\n猴", "Hey, \n猴", 7},
+	{"double_asian_runes", " 你\x1b[8m好.", " 你好.", 6},
 }
 
 func TestStrip(t *testing.T) {