Handle negative line numbers in error messages

[yuhan0]

(partially fixes) #3687 I took the opportunity to refactor some of the rx forms and add documentation, let me know if these should be separated out or squashed.

---

Before submitting the PR make sure the following things have been done (and denote this by checking the relevant checkboxes):

• [ ] The commits are consistent with our contribution guidelines
• [x] You've added tests (if possible) to cover your change(s)
• [x] All tests are passing (eldev test)
• [ ] All code passes the linter (eldev lint) which is based on elisp-lint and includes
  • byte-compilation, checkdoc, check-declare, packaging metadata, indentation, and trailing whitespace checks.
• [ ] You've updated the changelog (if adding/changing user-visible functionality)
• [ ] You've updated the user manual (if adding/changing user-visible functionality)

Thanks!

If you're just starting out to hack on CIDER you might find this section of its manual extremely useful.

[vemv]

LGTM - great work!

Did you check that there's coverage for all code paths in

https://github.com/clojure-emacs/cider/pull/3688/commits/1378a72b3b9de7d6d11e5a54dc327f83a53b404b https://github.com/clojure-emacs/cider/pull/3688/commits/de162d58c4fc452ea04cd0aef33593783980fef4

?

[yuhan0]

Yup, the existing cider-clojure-runtime-error-regexp tests cover both those cases:

Execution error (ArithmeticException) at foo/foo (src/haystack/parser.cljc:4). where either (ArithmeticException) or foo/foo may be missing