COMPMID-1008: Fix Doxygen issues

Change-Id: Ie73d8771f85d1f5b059f3a56f1bbd73c98e94a38
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/124723
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/graph2/printers/DotGraphPrinter.h b/arm_compute/graph2/printers/DotGraphPrinter.h
index 3b1879c..0efdf77 100644
--- a/arm_compute/graph2/printers/DotGraphPrinter.h
+++ b/arm_compute/graph2/printers/DotGraphPrinter.h
@@ -34,6 +34,7 @@
 {
 namespace graph2
 {
+/** Graph printer visitor. */
 class DotGraphVisitor final : public DefaultNodeVisitor
 {
 public: