Fix typographical errors

[Pricstas]

This pull request resolves typographical errors in comments and documentation across multiple files to improve readability and adherence to grammatical standards. The following changes have been made:

1. adr-006-fraud-service.md:

   • Corrected "a enum type" to "an enum type."

2. validation.go:

   • Fixed "a Accessor" to "an Accessor."

3. root.go:

   • Updated "a SHA-256 hasher" to "an SHA-256 hasher."

4. options.go:

   • Changed "a interval" to "an interval."

Files Updated:

• docs/adr/adr-006-fraud-service.md
• share/eds/validation.go
• share/root.go
• share/shwap/p2p/discovery/options.go

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Notes:

• These changes are limited to comments and documentation.
• No functional changes have been introduced.

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Checklist:

• Grammar corrections verified for accuracy.
• Targeted PR against the correct branch.
• Followed repository contribution guidelines.