Formatting errors in table of contents result in generic error message

[zorae]

Problem

OL cannot handle tables of contents that contain three or more pipe characters per line. When trying to save such a malformed TOC, the save fails with the following generic error message:

Sorry. There seems to be a problem with what you were just looking at.

We should at least give an error message that lets the librarian know there was a formatting error in the TOC.

Reproducing the bug

1. Edit any edition
2. In the table of contents section, enter the following:
   * 1. | Foreword | Lili Elbe | 4
3. Attempt to save the edit

• Expected behavior:
  The page prevents you from pressing the save button and explains that you have to resolve formatting issues in the table of contents.
• Actual behavior:
  You can press save, but it leads to a generic error message. Any edits you made will be lost unless you navigate back and your browser hasn’t purged the page from its cache.

Context

• Browser (Chrome, Safari, Firefox, etc): Safari
• OS (Windows, Mac, etc): iPad
• Logged in (Y/N): Y
• Environment (prod, dev, local): prod

Breakdown

Requirements Checklist

• [ ]

Related files

Stakeholders

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[schu96]

I think this is a duplicate of #10314