Add images and fix format, add child macro

Gateway shapes are used to indicate when parallel processing can and cannot occur in the workflow as well as what path the workflow takes depending on specific conditions.

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gateway_fork gateway_fork

Fork

This Gateway shape allows you to indicate the start of parallel processing of the workflows.
The Name property of this shape defaults to Fork.

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gateway_join gateway_join

Join

This Gateway shape allows you to indicate that waiting is required until parallel workflows complete before proceeding to the next action.
The Name property of this shape defaults to Join.

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gateway_decision gateway_decision

Decision

This Gateway shape allows you to determine what the next step is based on a specific condition being true or false.
The following table describes the shape's properties.

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