Empty template for nbsphinx_input_prompt and nbsphinx_output_prompt lead to TypeError: not all arguments converted during string formatting #10792
Description
Describe the bug
In my documentation, my idea was to hide the prompts. I wanted to be clever and just use an empty template for nbsphinx_input_prompt and nbsphinx_output_prompt. However, this lead to the following exception: TypeError: not all arguments converted during string formatting.
How to Reproduce
nbsphinx_input_prompt =nbsphinx_output_prompt = ""
Expected behavior
Maybe the filling of the variable could be more forgiving? So %s is only inserted in the template if such a variable is available in the template in the first place? I think this is better than tempering with HTML and CSS.
Your project
not applicable
Screenshots
No response
OS
Win
Python version
3.10
Sphinx version
5.1
Sphinx extensions
No response
Extra tools
No response
Additional context
No response