Remove SET keyword from db creation (#1342)

Not supported on Cypher 5 (under which tests for this branch run), plus
it's confusing that the `SET` keyword is optional in Cypher 25 and not
supported in Cypher 5.

Author: stefano-ottolenghi

modules/ROOT/pages/queries/select-version.adoc

@@ -48,7 +48,7 @@ To select a default Cypher version when creating a database, add `DEFAULT LANGUA
 .Cypher 25
 [source,cypher]
 ----
-CREATE DATABASE actors SET DEFAULT LANGUAGE CYPHER 25
+CREATE DATABASE actors DEFAULT LANGUAGE CYPHER 25
 ----
 
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