[Merged by Bors] - chore(Data/Nat/Choose/Sum): refined the statement of Finset.sum_antidiagonal_choose_add.

[FMLJohn]

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In this pull request, we have refined the statement of the theorem Nat.sum_antidiagonal_choose_add. The original statement looked like:

theorem sum_antidiagonal_choose_add (d n : ℕ) :
    (∑ ij ∈ antidiagonal n, (d + ij.2).choose d) =
    (d + n).choose d + (d + n).choose (succ d) := ...

We change it to:

theorem sum_antidiagonal_choose_add (d n : ℕ) :
    (∑ ij ∈ antidiagonal n, (d + ij.2).choose d) =
    (d + n + 1).choose (d + 1) := ...

which looks much nicer.

[github-actions]

PR summary cbd80b83cf

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff

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You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

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No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[b-mehta]

Pretty clear improvement, thanks!

[b-mehta]

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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