Include ASCII characters in "na" table

Since we're now assigning "na" (narrow) characters width 1,
we can include the ASCII character ranges in the table.

Author: wedaly

runewidth_test.go

@@ -164,6 +164,7 @@ var runewidthtests = []struct {
 	{'\u0300', 0, 0},
 	{'\u2028', 0, 0},
 	{'\u2029', 0, 0},
+	{'a', 1, 1}, // ASCII classified as "na" (narrow)
 	{'⟦', 1, 1}, // non-ASCII classified as "na" (narrow)
 }
 

script/generate.go

@@ -92,12 +92,10 @@ func eastasian(out io.Writer, in io.Reader) error {
 				hi: r2,
 			})
 		case "Na":
-			if r1 > 0xFF {
-				na = append(na, rrange{
-					lo: r1,
-					hi: r2,
-				})
-			}
+			na = append(na, rrange{
+				lo: r1,
+				hi: r2,
+			})
 		case "N":
 			nu = append(nu, rrange{
 				lo: r1,