Update doc/component/FAQ.markdown

Author: nikic

doc/component/FAQ.markdown

@@ -56,7 +56,7 @@ includes the functionality of the former.
 How can I limit the impact of cyclic references in the AST?
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-NodeConnectingVisitor adds a parent reference, which introduces a cycle. This means that the AST can now only be collected by cycle garbage collector.
+NodeConnectingVisitor adds a parent reference, which introduces a cycle. This means that the AST can now only be collected by the cycle garbage collector.
 This in turn can lead to performance and/or memory issues. 
 
 To break the cyclic references between AST nodes `NodeConnectingVisitor` supports a boolean `$weakReferences` constructor parameter.