Add stemmer for other languages in the docs

Close #1740
Close #1349

docs/content/documentation/content/search.md

@@ -21,6 +21,9 @@ As each site will be different, Zola makes no assumptions about your search func
 the JavaScript/CSS code to do an actual search and display results. You can look at how this site
 implements it to get an idea: [search.js](https://github.com/getzola/zola/tree/master/docs/static/search.js).
 
+If you are using a language other than English, you will also need to include the corresponding JavaScript stemmer file.
+See <https://github.com/weixsong/lunr-languages#in-a-web-browser> for details.
+
 ## Configuring the search index
 In some cases, the default indexing strategy is not suitable. You can customize which fields to include and whether
 to truncate the content in the [search configuration](@/documentation/getting-started/configuration.md).