chore: use inheritdoc tag

[horsefacts]

Motivation

Reduce duplication in natspec comments by using the @inheritdoc tag.

Merge Checklist

Choose all relevant options below by adding an x now or at any time before submitting for review

• [x] The PR title adheres to the conventional commits standard
• [x] The PR has been tagged with change type label(s) (i.e. documentation, feature, bugfix, or chore)
• [x] The PR's changes adhere to all the requirements in the contribution guidelines
• [x] All commits have been signed

Additional Context

This PR includes an unrelated fix to a fuzz test missing a vm.assume.

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PR-Codex overview

Detailed summary

• Added a new function isMigrated() to the IKeyRegistry interface to check if the contract has been migrated.
• Added a new function verifyFidSignature() to the IIdRegistry interface to verify if a signature was produced by the custody address that owns an fid.
• Added documentation comments to various functions and contracts to improve readability and understanding.
• Minor code refactoring and improvements.

The following files were skipped due to too many changes: src/IdRegistry.sol, src/StorageRegistry.sol

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[github-actions[bot]]

Coverage after merging horsefacts/inheritdoc into main will be

98.65%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src
Bundler.sol	100%	100%	100%	100%
FnameResolver.sol	100%	100%	100%	100%
IdRegistry.sol	100%	100%	100%	100%
KeyRegistry.sol	100%	100%	100%	100%
RecoveryProxy.sol	100%	100%	100%	100%
StorageRegistry.sol	100%	100%	100%	100%
src/lib
EIP712.sol	50%	100%	50%	50%	19
Signatures.sol	100%	100%	100%	100%
TransferHelper.sol	0%	0%	0%	0%	12, 17, 20, 20, 20
TrustedCaller.sol	100%	100%	100%	100%
src/validators
SignedKeyRequestValidator.sol	100%	100%	100%	100%