Fix query parsers doc related to vector search (#3799)

Author: ilariapet

solr/solr-ref-guide/modules/query-guide/pages/other-parsers.adoc

@@ -1002,11 +1002,13 @@ These parameters would be defined in `solrconfig.xml`, in the `defaults` section
 
 For more information about the possibilities of nested queries, see Yonik Seeley's blog post https://lucidworks.com/2009/03/31/nested-queries-in-solr/[Nested Queries in Solr].
 
-== Neural Query Parsers
+== Vector Query Parsers
 
-There is currently one Query Parser in Solr to provide Neural Search: `knn`.
+There are currently three Query Parsers in Solr to provide Vector Search:
 
-KNN stands for k-nearest neighbors.
+- `knn`: matches k-nearest neighbours (knn) documents to the target vector.
+- `knn_text_to_vector`: encode a textual query to a vector using a dedicated Language Model and matches knn documents to such query vector.
+- `vectorSimilarity`: matches documents whose similarity with the target vector is a above a minimum threshold.
 
 Details are documented further in the section xref:query-guide:dense-vector-search.adoc[].