Merge pull request #75 from sharmatime/patch-4

Update 16-file-formats.md

Author: mr-c

_episodes/16-file-formats.md

@@ -22,6 +22,9 @@ a file format initially for quick development before sharing your tool with
 others. You can browse existing file format listings for IANA [here][IANA] and
 for EDAM [here][EDAM].
 
+In the next tutorial, we explain  the `$namespace` and `$schema` section of the
+document in greater detail, so don't worry about these for now.  
+
 Note that for added value `cwltool` can do some basic reasoning based on file
 formats and warn you if there seem to be some obvious mismatches.