Added a new section named CodeTailorTest with four test questions

[xinyinghou]

Added a new section CodeTailorTest under _sources for testing. It includes five pages:

• solution_per_puzzle: An example Python question intended to present a solution-level personalized puzzle with paired distractors where applicable.
• multi_level_per_puzzle: An example Python question intended to present a solution-and-block-level personalized puzzle with paired distractors where applicable.
• java_solution_per_puzzle: An example Java question intended to present a solution-level personalized puzzle with paired distractors where applicable.
• java_multi_level_per_puzzle: An example Java question intended to present a solution-and-block-level personalized puzzle with paired distractors where applicable.

Updates:

• included a toctree page
• added reveal sources

Note: Since test cases are automatically reformatted from the question to the backend, a strict format is required.

[bnmnetp]

You still have not added CodeTailorTest/toctree.rst to the main index.rst file.