[Merged by Bors] - chore(Nat/Fib/Basic): fix names and csimp

[astrainfinita]

and add a csimp lemma to connect the existing Nat.fastFib.

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[github-actions]

PR summary 9493b30b5d

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

+ fastFibAux_bit_false
+ fastFibAux_bit_true
+ fastFibAux_eq
+ fastFib_eq
+ fib_eq_fastFib

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).

[eric-wieser]

bors merge

Thanks!

As a follow-up, perhaps we should make all the fastFib results private? That's perhaps a question for Zulip, and certainly a problem for another PR.

[mathlib-bors]

Pull request successfully merged into master.

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