Add missing deprecation warnings

[pl-github]

When switching the tests to PHPUnit 9, a few errors occurred because some methods were removed in PHPUni 9 that did not yet give a deprecation warning in PHPUnit 8.

What I have changed:

• Assert::contains()
  • added deprecation warning
  • removed testAssertThatContains() (seems to be the normal behavior for deprecated code)
• TestCase:: expectExceptionMessageRegExp()
  • added deprecation warning
  • replaced calls in tests with expectExceptionMessageMatches() to supress warnigs in test runs
• TestCase::setUseErrorHandler()
  • added deprecation warning

[sebastianbergmann]

Thank you for your contribution. I appreciate the time you invested in preparing this pull request. However, I have decided not to merge it.

assertContains() is not deprecated, and neither is contains(). expectExceptionMessageRegExp() and setUseErrorHandler() have @deprecated annotations ("soft deprecation") which has to be enough as I do not think that we should add "hard deprecations" in a bugfix release.

[pl-github]

You are right, it is only a small benefit and I didn`t know about the soft / hard deprecation strategy.

Many thanks for your continuous work on PHPUnit.

Its true assertContains() isnt deprecated, but for me contains() looks deprecated, too.

    /**
     * @deprecated Use containsEqual() or containsIdentical() instead
     */
    public static function contains($value, bool $checkForObjectIdentity = true, bool $checkForNonObjectIdentity = false): TraversableContains