Merge pull request #45 from christian-monch/fix-export-doc

extend push to to describe export behavior

datalad_next/patches/push_to_export_remote.py

@@ -245,9 +245,15 @@ def _transfer_data(repo: AnnexRepo,
 push.Push.__doc__ += """\
 
 
-Features added by the datalad-next extension
-
-Transparently transfer data to git-annex special remotes in export-mode (`exporttree=yes`), whenever ...
+    The following feature is added by the datalad-next extension:
+
+    If a target is a git-annex special remote that has "exporttree" set to
+    "yes", push will call 'git-annex export' to export the current HEAD to the
+    remote target. This will usually result in a copy of the file tree, to which
+    HEAD refers, on the remote target. A git-annex special remote with
+    "exporttree" set to "yes" can, for example, be created with the datalad
+    command "create-sibling-webdav" with the option "--mode=filetree" or 
+    "--mode=filetree-only".
 """
 push.Push._params_["force"] = Parameter(
     args=("-f", "--force",),