Fix typos across multiple files

[vipocenka]

This PR addresses minor typos in various files across the project to enhance clarity and maintain a consistent codebase. Each change corrects a grammatical or spelling error in comments or documentation, without modifying the logic or functionality of the code.

Summary of Changes

• Corrected grammar in comments for better understanding.
• Updated files:
  • event.go
  • reflect.go
  • type_test.go
  • exec.go
  • errors.go
  • engine.go
  • iterator.go
  • iterator_fast.go
  • contract.go
  • protocol.go
  • extension_utilities.go
  • unconfirmed.go