Add ALL keyword to RETURN clause as part of GQL compliance

Author: gem-neo4j

modules/ROOT/pages/appendix/gql-conformance/supported-mandatory.adoc

@@ -68,8 +68,7 @@ The only way to guarantee row order in Neo4j is to use xref:clauses/order-by.ado
 | 14.11
 | <return statement>
 | xref:clauses/return.adoc[`RETURN`]
-| GQL defines the option to specify `RETURN ALL` (functionally equivalent to using `RETURN` on its own).
-This is currently not available in Cypher.
+|
 
 | 16.2
 | <limit clause>

modules/ROOT/pages/clauses/return.adoc

@@ -236,3 +236,26 @@ The `Movie` node `'Man of Tai Chi'` is returned by the query, but only once (wit
 d|Rows: 1
 |===
 
+[[return-all-results]]
+== RETURN ALL
+
+Returning all results can also be accomplished by explicitly including `ALL` in the `RETURN`.
+The `RETURN ALL` keyword was introduced as part of Cypher's xref:appendix/gql-conformance/index.adoc[], and using it is functionally the same as using simple `RETURN`.
+
+.Query
+[source, cypher]
+----
+MATCH (p:Person {name: 'Keanu Reeves'})-->(m)
+RETURN ALL m
+----
+
+The same node is returned twice, as there are two relationships connecting to it from `'Keanu Reeves'`.
+
+.Result
+[role="queryresult",options="header,footer",cols="1*<m"]
+|===
+| m
+| {"title":"Man of Tai Chi","released":2013}+
+| {"title":"Man of Tai Chi","released":2013}+
+d|Rows: 1
+|===

modules/ROOT/pages/deprecations-additions-removals-compatibility.adoc

@@ -134,6 +134,25 @@ Several  xref:clauses/transaction-clauses.adoc#query-listing-transactions[`SHOW
 * The current query-related columns — `currentQuery`, `currentQueryId`, `parameters`, `planner`, `runtime`, `indexes`, `currentQueryStartTime`, `currentQueryElapsedTime`, `currentQueryCpuTime`, `currentQueryIdleTime`, and `currentQueryStatus` — now return `null` when no query is executing.
 |===
 
+=== New features
+
+[cols="2", options="header"]
+|===
+| Feature
+| Details
+
+a|
+label:functionality[]
+label:new[]
+[source, cypher, role=noheader]
+----
+MATCH (n)
+RETURN ALL n.prop AS prop
+----
+| The keyword `ALL` can now be added after a xref:clauses/return.adoc#return-all-results[RETURN] as the explicit form of a `RETURN` without duplicate removal.
+
+|===
+
 [[cypher-deprecations-additions-removals-5.26]]
 == Neo4j 5.26