The current link points to an obsolete site, which is no longer maintained.
Co-authored-by: Stefan Walter <67258699+rd-stefan-walter@users.noreply.github.com>
Adds conceptual documentation for stemming, including:
* An overview of why stemming is helpful in search
* Algorithmic vs. dictionary stemming
* Token filters used to control stemming, such as `stemmer_override`, `keyword_marker`, and `conditional`