Add textproc/wikiman

Wikiman is an offline search engine for manual pages, Arch Wiki, Gentoo
Wiki and other documentation.

Wikiman provides an easy interface for browsing documentation without the
need to be exact and connected to the internet. This is achieved by
utilizing full text search for wikis, partial name and description matching
for man pages, and fuzzy filtering for search results.

WWW: https://github.com/filiparag/wikiman

PR: 249134
Submitted by: Filip Parag <filip@parag.rs>