feat(Combinatorics/SimpleGraph/Paths): some cycle lemmas are true for circuits

[SnirBroshi]

Add IsCircuit.{not_of_nil,ne_bot,three_le_length} by using their corresponding IsCycle proofs.
Also golfs a bit.

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[github-actions]

PR summary def28638ef

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

+ IsCircuit.ne_bot
+ IsCircuit.not_of_nil
+ IsCircuit.three_le_length

You can run this locally as follows

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

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

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

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No changes to technical debt.

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/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).