Lean Manual

Stream: lean4

[Andrey Cheremskoy]

I've notice in the Lean Manual that Tactics appears twice in section 10 and then in section 15.
Also these two sections has the same content.
image.png
Also I see that the issue is in the SUMMARY.md file.
I created a PR with the fix for this issue.
https://github.com/leanprover/lean4/pull/927