Add a section for vector functions in the doc.

Author: afoucret

docs/reference/query-languages/esql/_snippets/lists/vector-functions.md

@@ -0,0 +1,7 @@
+* <<esql-knn>>
+* <<esql-v_cosine>>
+* <<esql-v_dot_product>>
+* <<esql-v_hamming>>
+* <<esql-v_l1_norm>>
+* <<esql-v_l2_norm>>
+* <<esql-v_magnitude>>

docs/reference/query-languages/esql/esql-functions-operators.md

@@ -80,6 +80,12 @@ mapped_pages:
 :::
 ::::
 
+::::{dropdown} Vector functions
+:open:
+:::{include} _snippets/lists/vector-functions.md
+:::
+::::
+
 ::::{dropdown} Multi value functions
 :open:
 :::{include} _snippets/lists/mv-functions.md

docs/reference/query-languages/esql/functions-operators/vector-functions.md

@@ -0,0 +1,48 @@
+---
+applies_to:
+  stack: preview
+  serverless: preview
+navigation_title: "Vector functions"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/esql-functions-operators.html#esql-vector-functions
+---
+
+# {{esql}} vector functions [esql-vector-functions]
+
+{{esql}} supports vector functions for dense vector similarity calculations and k-nearest neighbor search.
+
+These functions are primarily used for:
+- Computing similarity between dense vectors using various similarity metrics
+- Finding the k-nearest neighbors in vector space
+- Calculating vector magnitudes and norms
+
+:::{note}
+Vector functions are currently in **preview** and may change in future versions. 
+They work with `dense_vector` fields and require appropriate field mappings.
+:::
+
+{{esql}} supports these vector functions:
+
+:::{include} ../_snippets/lists/vector-functions.md
+:::
+
+:::{include} ../_snippets/functions/layout/knn.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_cosine.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_dot_product.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_hamming.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_l1_norm.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_l2_norm.md
+:::
+
+:::{include} ../_snippets/functions/layout/v_magnitude.md
+:::