code: @Factory
      public static Matcher<? super CharSequence> pattern(String regex) {
          return pattern(Pattern.compile(regex));
      }
docs: Creates a matcher that matches if the examined {@link CharSequence} matches the specified
  regular expression.
  
  For example:
  <pre>assertThat("myStringOfNote", pattern("[0-9]+"))</pre>
  
  @param regex the regular expression that the returned matcher will use to match any examined {@link CharSequence}
  @return the matcher