Fix typographical errors in Documentation, Tests, and Code

[Marcofann]

This PR resolves several typographical errors across multiple files in the codebase. These changes are focused on improving the clarity and accuracy of documentation, comments, and code.

Changes:

1. app/migrate_module_account_test.go:

   • Fixed "an pre-initialized" to "a pre-initialized."

2. Documentation Files:

   • docs/cli/axelard_keys_import.md
   • docs/cli/axelard_query_gov_proposals.md
   • docs/cli/axelard_tx_gov_submit-proposal.md
   • docs/cli/axelard_tx_gov_submit-proposal_execute-contract.md
   • docs/cli/axelard_tx_gov_submit-proposal_unpin-codes.md
   • Corrected various minor typos for better readability.

3. x/axelarnet/keeper/hooks_test.go:

   • Corrected "not an hex address" to "not a hex address."

4. x/vote/types/vote_router.go:

   • Fixed "an handler" to "a handler."