Currently regexes in Pattern Tokenizer docs are escaped (it seems according to Java rules). I think it is better not to escape them because JSON escaping should be automatic in client libraries, and string escaping depends on a client language used. The default pattern is `\W+`, not `\\W+`.
Closes#6615
Add `irish` analyzer
Add `sorani` analyzer (Kurdish)
Add `classic` tokenizer: specific to english text and tries to recognize hostnames, companies, acronyms, etc.
Add `thai` tokenizer: segments thai text into words.
Add `classic` tokenfilter: cleans up acronyms and possessives from classic tokenizer
Add `apostrophe` tokenfilter: removes text after apostrophe and the apostrophe itself
Add `german_normalization` tokenfilter: umlaut/sharp S normalization
Add `hindi_normalization` tokenfilter: accounts for hindi spelling differences
Add `indic_normalization` tokenfilter: accounts for different unicode representations in Indian languages
Add `sorani_normalization` tokenfilter: normalizes kurdish text
Add `scandinavian_normalization` tokenfilter: normalizes Norwegian, Danish, Swedish text
Add `scandinavian_folding` tokenfilter: much more aggressive form of `scandinavian_normalization`
Add additional languages to stemmer tokenfilter: `galician`, `minimal_galician`, `irish`, `sorani`, `light_nynorsk`, `minimal_nynorsk`
Add support access to default Thai stopword set "_thai_"
Fix some bugs and broken links in documentation.
Closes#5935
Clinton Gormley
Simon Willnauer
Mikhail Korobov
Robert Muir
Richard Boulton
Yousef
Adrien Grand