KafkaSource topics becomes KafkaSource topic

We've improved the consistency of the source by aligning the spelling of the topics parameter to singular. This was done as part of the December 6th release but this part of the documentation wasn't updated.

Author: jmcx

docs/sources/kafka.md

@@ -6,7 +6,7 @@ Consumes events from [Apache Kafka](https://kafka.apache.org/). Can be used with
 With `tmctl`:
 
 ```
-tmctl create source kafka --bootstrapServers kafka.example.com:9092 --topics <topic> --groupID <groupID> --auth.username <user> --auth.password.value <pass>  --auth.saslEnable true --auth.tlsEnable true --auth.securityMechanism PLAIN
+tmctl create source kafka --bootstrapServers kafka.example.com:9092 --topic <topic> --groupID <groupID> --auth.username <user> --auth.password.value <pass>  --auth.saslEnable true --auth.tlsEnable true --auth.securityMechanism PLAIN
 ```
 
 On Kubernetes:
@@ -20,7 +20,7 @@ spec:
   groupID: test-consumer-group
   bootstrapServers:
     - kafka.example.com:9092
-  topics:
+  topic:
     - test-topic
   auth:
     saslEnable: true
@@ -69,7 +69,7 @@ spec:
   groupID: test-consumer-group
   bootstrapServers:
     - kafka.example.com:9092
-  topics:
+  topic:
     - test-topic
   auth:
     saslEnable: true
@@ -110,7 +110,7 @@ spec:
   groupID: test-consumer-group
   bootstrapServers:
     - kafka.example.com:9093
-  topics:
+  topic:
     - test-topic
   auth:
     saslEnable: true
@@ -144,7 +144,7 @@ spec:
 In order to configure the adapter correctly the following fields are mandatory:
 
 - `boostrapservers`
-- `topics`
+- `topic`
 - `salsEnable`
 
 ### Status