chore: enhance documentation grammar and readability

[Ishiezz]

Description

This PR addresses several grammatical inconsistencies and typos found in the documentation to improve clarity and professional presentation.

Changes

• CONTRIBUTING.md: Added missing articles ("the", "A") for better flow.
• pkg/gofr/datasource/README.md: Corrected phrasing ("improving" -> "improve", "in scope" -> "in the scope") and fixed minor grammatical errors.

These small enhancements ensure the documentation maintains a high standard of quality.