sway-book: fix forc call examples

[zees-dev]

Description

This pull request introduces updates to the documentation and examples for the forc call command, improving clarity, organization, and usability.
The most significant changes include restructuring the documentation into a new file, updating the book summary to reflect this change, and enhancing the examples in the codebase for better readability.

Added dedicated section for forc-call under testing heading.

Documentation Updates:

• New Documentation File for forc call: The detailed documentation for the forc call command has been moved to a new file, docs/book/src/forc/plugins/forc_client/forc_call_docs.md. This includes comprehensive usage examples, parameter encoding details, and troubleshooting tips.
• Removal of Old Documentation: The old forc_call.md file has been removed, as its content has been migrated to the new structured format.

Book Summary Update:

• Updated SUMMARY.md: The book summary has been updated to include a link to the new forc call documentation under the "Testing" section for better navigation.

Code Example Enhancements:

• Improved Examples in call.rs: Examples in the forc call command's code file (forc-plugins/forc-client/src/cmd/call.rs) have been reformatted for clarity. Each example now uses markdown-style code blocks and descriptive headings, making them easier to follow.

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[kayagokalp]

The current change looks good to me but we want to fix #7138 sooner or later so that the invalid title and random formatting stuff (forc-call docs being italic) does not happen.