## Summary

- Remove `RDoc::AnonClass` class and file (documented as "never used")
- Remove `Darkfish::VERSION` (unreferenced)
- Remove `Formatter::InlineTag` struct (unused after inline parser
rewrite)
- Remove `ToHtmlCrossref::CLASS_REGEXP_STR` and `METHOD_REGEXP_STR`
(aliased but unused within the file)

### Process & tools used

1. **Detect candidates** — Used `detect_dead_constants` from
[Rubydex](https://github.com/Shopify/rubydex) to find constants with
zero resolved references in `lib/`. Got 22 candidates.
2. **Filter out false positives** — Grepped for actual usage of each
candidate, catching private constants used internally, dynamic access
via `const_defined?`/`const_get`, default parameters, and generated code
(Racc).
3. **Remove confirmed dead code** — Deleted 5 constants and 1
class+file.
4. **Run full test suite** — Caught that one deletion (`RI::Formatter`)
broke a `require_relative` in `ri/driver.rb`, so restored it. Final run:
2384 tests, 0 failures.