textproc/nuspell: update to 4.2.0
- Bump required C++ version after https://github.com/nuspell/nuspell/commit/43130b3b7bfe
- Shared library is default after https://github.com/nuspell/nuspell/commit/2c0189902e2c
Changes: https://github.com/nuspell/nuspell/releases/tag/v4.2.0
Reported by: GitHub (watch releases)