Doc improvement: add comment describing what convolve does

[metric-space]

Description

This is a suggestion for doc improvement.
The use of convolution in average calculation (in the blackjack tutorial) doesn't jump out unless you've used the operation in the past. Felt a comment might aid someone else a bit lost as to why np.convolve is used

Type of change

• This change requires a documentation update

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[pseudo-rnd-thoughts]

Thanks for the PR and comment. You are correct that the current code is weird and isn't well explained but I think the comment can be significantly simpler and not explain how convolve works.
Could the comment just be next to the first case that says, "code ... is used to compute a rolling average of the data to provide a more smooth graph"

[metric-space]

@pseudo-rnd-thoughts What you said makes more sense than what I had. Do I go ahead and put that line in or would you do that (in a separate PR and I can close this one )?

[pseudo-rnd-thoughts]

@metric-space Im happy for you to use this PR