MAINTAINERS: add bindesc documentation to bindesc area

adds doc/services/binary_descriptors/index.rst to bindesc area

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

MAINTAINERS.yml

@@ -399,6 +399,7 @@ Binary Descriptors:
   maintainers:
     - yonsch
   files:
+    - doc/services/binary_descriptors/
     - subsys/bindesc/
     - include/zephyr/bindesc.h
     - samples/subsys/bindesc/