add missing backtick

Author: JPryce-Aklundh

modules/ROOT/pages/clauses/union.adoc

@@ -133,7 +133,7 @@ For example, the below query xref:functions/aggregating.adoc#functions-count[cou
 
 [NOTE]
 The below query uses an empty xref:subqueries/call-subquery.adoc#variable-scope-clause[variable scope clause]: `CALL () { ... }` (introduced in Neo4j 5.23).
-If you are using an older version of Neo4j, use `CALL { ... } instead.
+If you are using an older version of Neo4j, use `CALL { ... }` instead.
 For more information, see xref:subqueries/call-subquery.adoc#import-variables[CALL subqueries -> Importing variables].
 
 .Query

modules/ROOT/pages/functions/graph.adoc

@@ -129,7 +129,7 @@ Returns all nodes from a subset of graphs that have a `tags` property containing
 
 [NOTE]
 The above query uses an empty xref:subqueries/call-subquery.adoc#variable-scope-clause[variable scope clause]: `CALL () { ... }` (introduced in Neo4j 5.23).
-If you are using an older version of Neo4j, use `CALL { ... } instead.
+If you are using an older version of Neo4j, use `CALL { ... }` instead.
 For more information, see xref:subqueries/call-subquery.adoc#import-variables[CALL subqueries -> Importing variables].
 
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@@ -165,7 +165,7 @@ Returns all nodes from all graphs on the current composite database.
 
 [NOTE]
 The above query uses an empty xref:subqueries/call-subquery.adoc#variable-scope-clause[variable scope clause]: `CALL () { ... }` (introduced in Neo4j 5.23).
-If you are using an older version of Neo4j, use `CALL { ... } instead.
+If you are using an older version of Neo4j, use `CALL { ... }` instead.
 For more information, see xref:subqueries/call-subquery.adoc#import-variables[CALL subqueries -> Importing variables].
 
 ======