Do not mention metadata

Author: jl-wynen

docs/examples/POWGEN_data_reduction.ipynb

@@ -171,8 +171,7 @@
     "\n",
     "We ultimately need to write the reduced data to a file.\n",
     "This could be done with the `result` we computed above.\n",
-    "But then we would have to provide all metadata manually.\n",
-    "Instead, we can use the pipeline to provide this metadata (in this case only the file name) as shown below.\n",
+    "But we can use the pipeline to provide additional parameters (in this case only the file name) as shown below.\n",
     "See also the [File output](https://scipp.github.io/sciline/recipes/recipes.html#File-output) docs of Sciline.\n",
     "\n",
     "For simplicity we write a simply xye file with 3 columns: $d$-spacing, intensity, standard deviation of intensity."