Remove <p> tags from question choice labels and hints
Remove <p> tags from question choice labels and hints

Upgrading Sphinx from 1.6 to 4.1 changes the compiled HTML output.
Questionnaire answer choices and hints may contain HTML formatting,
such as bold text or mathematical notations. Those HTML fragments
are written to the exercise YAML files in the RST build.
Sphinx 4.1 adds unwanted <p> tags to these lines and we must remove
them before writing the YAML output.

Question answer choice labels may not contain <p> since the HTML
specification does not allow <p> inside <label>.
The current implementation of the question feedback hints in
the MOOC-Grader does not allow <p> in the hint content.
(MOOC-Grader wraps the hint text in a <p> in the HTML template.)

Aalto-LeTech/a-plus-rst-tools,Aalto-LeTech/a-plus-rst-tools,Aalto-LeTech/a-plus-rst-tools