docs: Cummulative patch of added / replaced labels

To reference those section labels of the documentation, so they can be referenced
from the other parts of the documentation.

Signed-off-by: Sebastian Serewa <sebastian.serewa@huawei.com>

docs/hardware-support/boards/96b-nitrogen.rst

@@ -2,7 +2,7 @@
 ..
 .. SPDX-License-Identifier: CC-BY-4.0
 
-.. _nitrogen:
+.. _SupportedBoardNitrogen:
 
 96Boards Nitrogen
 #################

docs/hardware-support/boards/seco-imx8mm-c61.rst

@@ -2,6 +2,8 @@
 ..
 .. SPDX-License-Identifier: CC-BY-4.0
 
+.. _SupportedBoardSecoC61:
+
 SBC-C61 SECO
 ############
 

docs/hardware-support/boards/seco-intel-b68.rst

@@ -2,6 +2,8 @@
 ..
 .. SPDX-License-Identifier: CC-BY-4.0
 
+.. _SupportedBoardSecoB68:
+
 SBC-B68-eNUC SECO
 #################
 

docs/openharmony-quick-build.rst

@@ -2,6 +2,8 @@
 ..
 .. SPDX-License-Identifier: CC-BY-4.0
 
+.. _OpenHarmonyQuickBuild:
+
 OpenHarmony - Quick Build
 #########################