Simplify description of workflows and activities

Removed redundant wording in the workflows documentation.

Author: rmcdaniel

docs/defining-workflows/workflows.md

@@ -4,7 +4,7 @@ sidebar_position: 1
 
 # Workflows
 
-In Workflow, workflows and activities are defined as classes that extend the base `Workflow` and `Activity` classes provided by the framework. A workflow is a class that defines a sequence of activities that run in parallel, series or a mixture of both. 
+Workflows and activities are defined as classes that extend the base `Workflow` and `Activity` classes provided by the framework. A workflow is a class that defines a sequence of activities that run in parallel, series or a mixture of both. 
 
 You may use the `make:workflow` artisan command to generate a new workflow: