Fix typos across multiple files

[Marcofann]

This pull request resolves several minor typographical errors found across multiple files in the Polkadot SDK and Substrate repositories. The changes involve correcting grammar, spelling, and consistency issues without affecting the functional behavior of the code.

Summary of changes:

• Fixed incorrect articles (e.g., "a" → "an").
• Corrected grammatical issues in comments and documentation.
• Improved readability and clarity in code comments.

Files Modified:

1. location.rs - Corrected article usage in a comment.
2. parachain_consensus.rs - Fixed grammar in a log message.
3. snowbridge.rs (multiple instances) - Fixed grammatical inconsistencies.
4. CONTRIBUTING.md - Resolved typo in documentation.
5. meta_contributing.rs - Adjusted article usage in context explanations.
6. mod.rs - Corrected wording in comments.
7. block_builder.rs - Fixed article inconsistency.
8. generate_node_key.rs and inspect_node_key.rs - Improved hex encoding descriptions.
9. lib.rs (two instances) - Resolved typo in peer reputation descriptions.

[cla-bot-2021]

User @Marcofann, please sign the CLA here.