Fix from_h5mu_to_h5mu: use __merge__ instead of __inherits__

Author: DriesSchaumont

src/convert/from_10xh5_to_h5mu/config.vsh.yaml

@@ -29,7 +29,7 @@ functionality:
           description: Output h5mu file.
           example: output.h5mu
           direction: output
-          __inherits__: api_output.yaml
+          __merge__: api_output.yaml
         - name: "--uns_metrics"
           type: string
           description: Name of the .uns slot under which to QC metrics (if any).