doc: hide doxygen duplicate definition warnings
Sphinx/Breathe have a known problem with processing unnamed nested
structs and unions that cause a "Duplicate definition" warning.
Use our .known-issues filter to hide these in the HLD content.
#
-# Emulated devices
+# HLD warnings
#
-#
-^(?P<filename>[-._/\w]+/hld/hv-io-emulation.rst):(?P<lineno>[0-9]+): WARNING: Duplicate declaration.
+#^(?P<filename>[-._/\w]+/hld/hv-cpu-virt.rst):(?P<lineno>[0-9]+): WARNING: Duplicate declaration.
+^(?P<filename>[-._/\w]+/hld/[-._/\w]+.rst):(?P<lineno>[0-9]+): WARNING: Duplicate declaration.
