Flycheck 33

Note: The changelog for this release is incomplete.

New features and improvements

• The flycheck-verify-setup UI now includes buttons to re-enable manually
  disabled checkers and to try to re-enable automatically disabled checkers
  (command checkers are automatically disabled when their executable cannot be
  found). [GH-1755]
• Error explainers can now return URLs (to show a webpage) or functions (to
  use custom formatting). For example, the Rust checker now renders
  explanations using markdown-view-mode. [GH-1753]
• Enable checkers in many newer TreeSitter-based major modes (think *-ts-mode).

New syntax checkers

• Python with ruff. [GH-2033]

Breaking changes

• Drop support for Emacs 25.
• The variable flycheck-current-errors now contains errors in the order in
  which they were returned by checkers. In previous versions of Flycheck,
  this list was sorted by error position and severity. [GH-1749]