Update patterns/2-structured/document-your-guiding-principles.md

Co-authored-by: Nejc Habjan <hab.nejc@gmail.com>

Author: fgreinacher

patterns/2-structured/document-your-guiding-principles.md

@@ -124,7 +124,7 @@ All Trusted Committers of a project are published.
 * Europace AG
 * GitHub
 * Robert Bosch GmbH
-* Siemens' Inner Source strategy is built upon the guiding principles Documentation, Workflow, Transparency, Continuous Integration and Culture which are detailed in their Inner Source portal.
+* Siemens' Inner Source strategy is built upon the guiding principles of Documentation, Workflow, Transparency, Continuous Integration and Culture which are detailed in their Inner Source portal.
 
 ### Europace AG