[Matchers] improved diagnostics

many matchers (like the container/range matchers) provide only information that something is going wrong, but not necessarily what exactly. e.g. `UnorderedRangeEqualsMatcher` only prints the expected and actual values in the `describe()` method.

gmock's matchers for example provide provide a more detailed analysis what exactly is going wrong, compare https://github.com/google/googletest/blob/c875c4e2249ec124c24f72141b3780c22256fd44/googlemock/src/gmock-matchers.cc#L283-L476 for example. (e.g. which range elements differ between two ranges). it would be great if catch2 could also provide such analysis

Start with the UnorderedRangeEqualsMatcher and its describe() output, then compare the requested diagnostics with the linked GoogleMock matcher implementation. The issue does not name Catch2 files or tests; done would mean matchers such as the container and range matchers explain which elements differ, rather than only showing expected and actual values.

Written by the indexing model from the issue text.