Unified the variable-mapping description (#615)

* Unified the variable-mapping description

- business-rule-task
- script-tasks
- send-tasks

* Fixes #1
* Fixex #2

docs/components/modeler/bpmn/business-rule-tasks/business-rule-tasks.md

@@ -31,9 +31,9 @@ specifies the type of job workers should subscribe to (e.g. DMN).
 Use [task headers](/components/modeler/bpmn/service-tasks/service-tasks.md#task-headers) to pass static parameters to the job
 worker (e.g. the key of the decision to evaluate).
 
-Define [variable mappings](/components/concepts/variables.md#inputoutput-variable-mappings) to transform the
-variables passed to the job worker, or to customize how the variables of the job are merged
-in the process instance.
+Define [variable mappings](/components/concepts/variables.md#inputoutput-variable-mappings)
+the [same way as a service task does](/components/modeler/bpmn/service-tasks/service-tasks.md#variable-mappings)
+to transform the variables passed to the job worker, or to customize how the variables of the job merge.
 
 ## Additional resources
 

docs/components/modeler/bpmn/receive-tasks/receive-tasks.md

@@ -30,9 +30,10 @@ To correlate a message to the receive task, the message is published with the de
 
 Output variable mappings are used to customize how variables are merged into the process instance.
 These can contain multiple elements that specify which variables should be mapped.
-The `Process Variable Name` of an output denotes the variable name outside of the activity.
+The `Process Variable Name` of an output denotes the variable name outside the activity.
 
 Visit our documentation on [input and output variable mappings](/components/concepts/variables.md#inputoutput-variable-mappings) for more information on this topic.
+
 ## Additional resources
 
 ### XML representation

docs/components/modeler/bpmn/script-tasks/script-tasks.md

@@ -31,9 +31,9 @@ the type of job workers should subscribe to (e.g. `script`).
 Use [task headers](/components/modeler/bpmn/service-tasks/service-tasks.md#task-headers) to pass static parameters to the job
 worker (e.g. the script to evaluate). The community extension [Zeebe Script Worker](https://github.com/camunda-community-hub/zeebe-script-worker) requires certain attributes to be set in the task headers.
 
-Define [variable mappings](/components/modeler/bpmn/service-tasks/service-tasks.md#variable-mappings) to transform the
-variables passed to the job worker, or to customize how the variables of the job merge
-in the process instance.
+Define [variable mappings](/components/concepts/variables.md#inputoutput-variable-mappings)
+the [same way as a service task does](/components/modeler/bpmn/service-tasks/service-tasks.md#variable-mappings)
+to transform the variables passed to the job worker, or to customize how the variables of the job merge.
 
 ## Additional resources
 

docs/components/modeler/bpmn/send-tasks/send-tasks.md

@@ -33,8 +33,9 @@ way as a service task does. It specifies the type of job that workers should sub
 Use [task headers](/components/modeler/bpmn/service-tasks/service-tasks.md#task-headers) to pass static parameters to the job
 worker (e.g. the name of the topic to publish the message to).
 
-Define [variable mappings](/components/modeler/bpmn/service-tasks/service-tasks.md#variable-mappings) to transform the
-variables passed to the job worker, or to customize how the variables of the job merge in the process instance.
+Define [variable mappings](/components/concepts/variables.md#inputoutput-variable-mappings)
+the [same way as a service task does](/components/modeler/bpmn/service-tasks/service-tasks.md#variable-mappings)
+to transform the variables passed to the job worker, or to customize how the variables of the job merge.
 
 ## Additional resources