Fix typo in doc.

Co-authored-by: Viacheslav Chernyshev <[email protected]>

Author: garyrussell

spring-kafka-docs/src/main/asciidoc/kafka.adoc

@@ -5738,7 +5738,7 @@ The reason for the two properties is because, while you might want to retain onl
 
 Starting with version 2.8.4, you now can control which of the standard headers will be added to the output record.
 
-The there is a new property `whichHeaders`, which is a `BitSet`; for example, to suppress the addition of adding the stack trace header, use the following:
+There is a new property `whichHeaders`, which is a `BitSet`; for example, to suppress the addition of adding the stack trace header, use the following:
 
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 [source, java]