docs: add cidr_block to attribute reference of aws_vpc

[stefanfreitag]

Description

Added the missing cidr_block field in the attribute reference section.

Additionally,

• re-ordered attributes in the attribute reference section alphabetically
• changed in the argument reference section the format of three default values from plain text to code style.

Relations

Closes #38034 .

References

none

Output from Acceptance Testing

Not applicable as only documentation is updated by this pull request.

[github-actions]

Community Note

Voting for Prioritization

• Please vote on this pull request by adding a 👍 reaction to the original post to help the community and maintainers prioritize this pull request.
• Please see our prioritization guide for information on how we prioritize.
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request.

For Submitters

• Review the contribution guide relating to the type of change you are making to ensure all of the necessary steps have been taken.
• For new resources and data sources, use skaff to generate scaffolding with comments detailing common expectations.
• Whether or not the branch has been rebased will not impact prioritization, but doing so is always a welcome surprise.