Docs: Fix spelling typos

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: Ie7729b848b7284696d9b546b676cb4f31ab5db47
diff --git a/docs/integration_guide/source_structure/source_structure.rst b/docs/integration_guide/source_structure/source_structure.rst
index d7882f4..728b12f 100644
--- a/docs/integration_guide/source_structure/source_structure.rst
+++ b/docs/integration_guide/source_structure/source_structure.rst
@@ -7,7 +7,7 @@
 TF-M is designed to provide a user-friendly source structure to ease
 integration and service development. This document introduces the source
 structure and its design intention of TF-M. Additionally, the folders below are
-important for TF-M integration and descibed in a separate documents:
+important for TF-M integration and described in a separate documents:
 
 .. toctree::
     :maxdepth: 1