message: Add an example for `(?m)^` matching at end of text
  Fixes
diff: @@ -398,7 +398,7 @@ Notice that the `a+` matches either `a` or `A`, but the `b+` only matches
  `b`.
  Multi-line mode means `^` and `$` no longer match just at the beginning/end of
  -the input:
  +the input, but at the beginning/end of lines:
  ```
  # use regex::Regex;
  @@ -407,6 +407,15 @@ let m = re.find("line one\nline 2\n").unwrap();
  assert_eq!(m.as_str(), "line 2");
  ```
  +Note that `^` matches after new lines, even at the end of input:
  +
  +```
  +# use regex::Regex;
  +let re = Regex::new(r"(?m)^").unwrap();
  +let m = re.find_iter("test\n").last().unwrap();
  +assert_eq!((m.start(), m.end()), (5, 5));
  +```
  +
  Here is an example that uses an ASCII word boundary instead of a Unicode
  word boundary:
  