Fix trailing spaces in example output

muesli · muesli · commit cf7e7eac5cb4 · 2020-02-10T21:27:03.000+01:00
diff --git a/README.md b/README.md
@@ -103,7 +103,7 @@ s := padding.String("Hello", 8)
 fmt.Println(s)
 ```
 
-Result: `Hello   `
+Result: `Hello___` (the underlined portion represents 3 spaces)
 
 There is also a padding Writer, which is compatible with the `io.WriteCloser`
 interface:
