added block syntax to an IMPORTANT admonition

Author: rsill-neo4j

modules/ROOT/pages/clauses/clause-composition.adoc

@@ -129,7 +129,9 @@ In a Cypher query, read and write clauses can take turns.
 The most important aspect of read-write queries is that the state of the graph also changes between clauses.
 
 [IMPORTANT]
+====
 A clause can never observe writes made by a later clause, and will observe all writes done by the previous clauses.
+====
 
 As of Cypher 25, read and write clauses can be combined in any order.
 That is, a write clause followed by a read clause no longer requires a separating xref:clauses/with.adoc[`WITH`] clause in order for the read clause to observe the changes made by a preceding write clause.