Cleanup regex diagnostic output (#1947)

Cleanup regex diagnostic output (#1947)

* Include actual pattern in diagnostic output

* Fix char category name in diagnostic output

* Tighten Boyer Moore debug output

* Clean up diagnostic output from RegexCode and RegexNode

* Apply suggestions from code review

Co-Authored-By: Stephen Toub <stoub@microsoft.com>
* more

* display options and timeout

* Some random nits

* Update src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexBoyerMoore.cs

Co-Authored-By: Stephen Toub <stoub@microsoft.com>
* Github typo

Co-authored-by: Stephen Toub <stoub@microsoft.com>