Don't parse hyphens in Chars() unless escaped

parser.go

@@ -181,6 +181,8 @@ func parseMatcher(matcher string) (alphabet string, ranges [][]rune) {
 			}
 		} else if i+1 < len(runes) && runes[i] == '\\' {
 			alphabet += string(runes[i+1])
+		} else if runes[i] == '-' {
+			continue
 		} else {
 			alphabet += string(runes[i])
 		}

parser_test.go

@@ -114,7 +114,7 @@ func TestChars(t *testing.T) {
 	t.Run("unescaped hyphen", func(t *testing.T) {
 		node, ps := runParser("19-", Chars("0-9"))
 		require.Equal(t, "19", node.Token)
-		require.Equal(t, 2, ps.Pos)
+		require.Equal(t, "-", ps.Get()) // hyphen shouldn't have been parsed
 		require.False(t, ps.Errored())
 	})