patch with written back

[gerritbruening]

Applies to all cases where ge:patch has two surface children (which makes sense but is invalid).
Don't know whether we had any ideas how to render this. I could imagine a box with a dotted line.

For past discussion on this, see https://faustedition.uni-wuerzburg.de/wiki/index.php/Dokumentarisches_Markup#Beschriebene_R.C3.BCckseiten_eines_Zettels.

[gerritbruening]

DR has identified 2 H, p. 45 as a case ("Zeichengewirr")

http://dev.faustedition.net/document?sigil=2_H&page=177&view=facsimile_document#lbefore_7811_b ist gebastelt worden.