Always escape a slice of bytes

Use `formatString()` to format a value of type `[]byte` but
`formatSlice()` which formats the slice into an array of `uint8`.

Fixes #147

format/format.go

diff --git a/format/format.go b/format/format.go
index 226b892..38d5d79 100644
--- a/format/format.go
+++ b/format/format.go
@@ -143,9 +143,6 @@
 	case reflect.Ptr:
 		return formatValue(value.Elem(), indentation)
 	case reflect.Slice:
-		if value.Type().Elem().Kind() == reflect.Uint8 {
-			return formatString(value.Bytes(), indentation)
-		}
 		return formatSlice(value, indentation)
 	case reflect.String:
 		return formatString(value.String(), indentation)