change "transcribe" to "incomplete" in contents tab

[saracarl]

Molly at History Revealed writes:

My final question is one from my transcribers, and not new feature related. When on the Contents tab, is there a way to have the Action say "Incomplete" instead of "Transcribe"? It works that way under the Read tab, but I encourage everyone to use the Contents tab for efficiency in moving between documents, especially once transcribing of a Work is well underway. The transcribers get disappointed when they open a document only to discover it is nearly complete. While I encourage the crowd-source effort, they aren't keen on working on someone else's pages even when they haven't been touched in months.

I think we should consider this. The core question is "what is the purpose of the Contents tab"? If it's to help transcribers find and understand the status of works, then this change makes sense.